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zaterdag 3 juni 2017

Esquire en Bierista


As the co-founder and chairman of the Boston Beer Company, he has appeared in countless Sam Adams commercials over thirty years. And, while this always-smiling man is a regular guy like you and me while walking the street, the second he enters a bar Jim Koch becomes a celebrity.... Koch leaned in toward me, stared straight into my eyes, and whispered.
"You wanna know my secret? How I can drink beer all night long and never get drunk?"
In fact, I had always wondered that. Though this was the first time I'd ever formally met Koch, I'd "met" him in the past at a few beer festivals. Those sorts of events are always kind of Bacchanalian shit shows, with people imbibing dozens of beer samples in a short period and soon stumbling around large convention halls drunk of their asses. Brewers included. But not Koch, who I'd long noticed was always lucid, always able to hold court, and hold his own with those much younger than him. This billionaire brewing raconteur was doing likewise with me at 4 PM on a Thursday afternoon despite the fact we were both now several beers deep. So what was the secret?
"Yeast!"
"Yeast?"
"Active yeast. Like you get at the grocery store."
Koch told me that for years he has swallowed your standard Fleischmann's dry yeast before he drinks, stirring the white powdery substance in with some yogurt to make it more palatable.
"One teaspoon per beer, right before you start drinking."
He'd learned the trick from his good friend "Dr. Joe," a craft beer legend in his own right. Educated at Harvard with a troika of degrees (a BA, a JD, and an MBA), Koch is no slouch, but the late-Joseph Owades was a flat-out genius. With a PhD in biochemistry from Brooklyn Polytechnic Institute and an early job in the fermentation sciences department at Fleischmann's, Owades probably knew more about fermentation and alcohol metabolism than perhaps any man who has ever lived. Koch calls him, in fact, "The best brewer who's ever lived." He used that immense knowledge to eventually become a consultant for most of the progenitors of America's early craft brewing movement such as Anchor Brewing in San Francisco, New Amsterdam Brewing in New York, and, yes, the Boston Beer Company. There he became good friends with Koch, helped perfect Boston Lager, and passed on to Koch his little yeast secret.
...
You see, what Owades knew was that active dry yeast has an enzyme in it called alcohol dehydrogenases (ADH). Roughly put, ADH is able to break alcohol molecules down into their constituent parts of carbon, hydrogen, and oxygen. Which is the same thing that happens when your body metabolizes alcohol in its liver. Owades realized if you also have that enzyme in your stomach when the alcohol first hits it, the ADH will begin breaking it down before it gets into your bloodstream and, thus, your brain.
"And it will mitigate – not eliminate – but mitigate the effects of alcohol!" Koch told me.
In his final years Owades even patented a product called Prequel, an all-natural pill similarly designed to limit drunkenness. No companies wanted to deal with the potential liabilities of the product, and Owades died in 2005 at the age of 86 (www.esquire.com/food-drink/drinks/how-to/a26328/how-not-to-get-drunk/, BY AARON GOLDFARB FEB 1, 2015).

Ik geloof er niks van.

Samuel Adams brewer Jim Koch told Esquire Magazine  his secret for never getting drunk on copious amounts of his fine product: he swallows a teaspoon of yeast before every beer.
He claimed that the active ingredient in active dry yeast — an enzyme called alcohol dehydrogenase — breaks down the liquor in the stomach before the alcohol can get into your bloodstream and do the voodoo it does.
That sounded ridiculous for two reasons: 1. could yeast really break down alcohol before it gets to the brain? And 2. Why would we want to break down alcohol before it gets to our brain?
Koch needs to stay sober for professional reasons. We needed to get drunk for professional reasons — i.e. to test his theory.
o the Daily News Taste Kitchen filled Dr. Koch’s prescription — and got busy with some investigative journalism in the form of a full glass of Widow Jane bourbon.
With seven capsules of Red Star yeast rumbling in our stomachs, we downed extremely generous pours of the bourbon — far more than our normal adult dose — and did not get drunk.
...
There was no control group — in the Daily News Taste Kitchen, everyone gets to partake — but experts say our experiment and Koch’s experience have some validity.
“The extra enzyme helps to more rapidly break down the alcohol,” says Steven Isaacman, a director of Research at Nanometics, a pharmaceutical-industry lab.
Isaacman did point out one downside to our experiment — which we confirmed hours after our conversation.
“That much yeast is going to make your stomach grumble,” he adds. Grumble is an understatement; you’ll want to be near a bathroom for most of the morning after.
In the real world, bartenders weren’t that pleased with Koch’s buzz-kill pills.
“Part of the fun of drinking is getting tipsy!” says bartender Damien Suazo of Vintry Wine & Whiskey in the Financial District (www.nydailynews.com/life-style/eats/proof-yeast-block-tipsiness-article-1.1773243).

Alcohol dehydrogenases (ADH) (EC 1.1.1.1) are a group of dehydrogenase enzymes that occur in many organisms and facilitate the interconversion between alcohols and aldehydes or ketones with the reduction of nicotinamide adenine dinucleotide (NAD+ to NADH). In humans and many other animals, they serve to break down alcohols that otherwise are toxic, and they also participate in generation of useful aldehyde, ketone, or alcohol groups during biosynthesis of various metabolites. In yeast, plants, and many bacteria, some alcohol dehydrogenases catalyze the opposite reaction as part of fermentation to ensure a constant supply of NAD+.
...
The first-ever isolated alcohol dehydrogenase (ADH) was purified in 1937 from Saccharomyces cerevisiae (brewer's yeast).[10] Many aspects of the catalytic mechanism for the horse liver ADH enzyme were investigated by Hugo Theorell and coworkers.[11] ADH was also one of the first oligomeric enzymes that had its amino acid sequence and three-dimensional structure determined.[12][13][14]
In early 1960, it was discovered in fruit flies of the genus Drosophila.[15]
...
Clinical significance[edit]
Alcoholism[edit]
There have been studies showing that ADH may have an influence on the dependence on ethanol metabolism in alcoholics. Researchers have tentatively detected a few genes to be associated with alcoholism. If the variants of these genes encode slower metabolizing forms of ADH2 and ADH3, there is increased risk of alcoholism. The studies have found that mutations of ADH2 and ADH3 are related to alcoholism in Northeast Asian populations. However, research continues in order to identify the genes and their influence on alcoholism.[43]
Drug dependence[edit]
Drug dependence is another problem associated with ADH, which researchers think might be linked to alcoholism. One particular study suggests that drug dependence has seven ADH genes associated with it. These results may lead to treatments that target these specific genes. However, more research is necessary.[44] (https://en.wikipedia.org/wiki/Alcohol_dehydrogenase)

Can Yeast Really Keep You From Getting Drunk?
Does the Jim Koch trick actually work? [Photos: Kevin Liu]
A few weeks ago, Esquire ran a provocative piece claiming that Sam Adams founder Jim Koch uses a clever trick to avoid getting drunk during a long night of imbibing: he swallows active dry yeast to digest the alcohol before it can get into his system.
Today we'll look at the science of alcohol metabolism to find out if this trick could actually work.
HOW DO HUMANS DIGEST ALCOHOL?
When I wrote about alcohol metabolism before, I mentioned that humans metabolize alcohol in the liver. And while that's mostly true, it's more complicated than that.
When you drink alcohol, it travels from the mouth down the esophagus into the stomach. From here, many sources claim that about 20% of the alcohol you drink travels directly between the stomach and your blood vessels.1, 2
When I checked the research, it turns out that you directly absorb as much as 30% of alcohol through the stomach when you're drinking with food and as little as 10% without food.3 Since absorption through the stomach is slower than through the small intestines, this helps explain why we tend to get drunk more slowly when we're having our drinks with a meal.
Either way, though, the majority of alcohol eventually travels out the stomach into the small intestines, where the alcohol gets absorbed through the intestinal walls into the surrounding blood vessels.
The blood from the small intestines then goes through the liver, where the alcohol begins to be digested, but since the liver can't handle a whole lot of alcohol at a time, much of the alcohol passes through the liver without being digested. That alcohol circulates in the blood stream to the rest of your body and, well, gets you drunk.
Over time, the blood in your body continues to pass through the liver and your liver continues to process it, until you eventually convert all the alcohol in your blood into simple sugars or excrete it as acetic acid.
HOW DOES ACTIVE DRY YEAST HELP METABOLIZE ALCOHOL?
Most yeast has an enzyme called Alcohol Dehydrogenase (ADH). There are several different types of ADH and other types of ADH can be found in plants and animals as well.
Humans possess ADH in both our stomachs and in our livers. The version we harbor can process not just alcohol from spirits, but also other alcohols that would be harmful to our bodies. In that way, our ADH protects us from small amounts of toxins that might occur in fermented foods and as a result of the fermentation that occurs during our own digestive processes.
The version of ADH found in yeast, specifically baker's yeast, is different than the ADH found naturally in the human body.4 It isn't as robust as the ADH in a human, but it can digest alcohol. How? Read on...
If you're a homebrewer or spirits enthusiast, you may know that yeast are responsible for converting simple sugars into, among other things, carbon dioxide and alcohol. So if you know them best for turning stuff into alcohol, why would they be used to transform alcohol back into non-hangover-inducing matter?
The short answer is that the ADH in yeast are part of a complex regulatory system. The yeast themselves digest sugars into ethanol, but yeast die when too much ethanol is present, so they had to evolve a system that would allow them to keep digesting optimally without committing suicide-by-alcohol.
How does all of this relate to Koch's trick? Follow my logic here:
Jim Koch referred specifically to active dry yeast
Fleischmann's brand active dry yeast contains only the yeast strain Saccharomyces cerevisiae 5
Saccharomyces cerevisiae yeast contains the ADH enzyme that digests ethanol.4
Big important takeaway: don't go swallowing random yeast strains. I'm looking at you homebrewers out there. As you well know, yeast can vary drastically depending on strain and geography. Much of the yeast used for brewing is Saccharomyces cerevisiae, but not all of it. I don't think you could get hurt eating other yeast used for brewing, but I haven't researched it in depth, so I can't recommend it.
SO... DOES IT WORK?
Believe it or not, I think so.
Almost as soon as the Esquire article was posted, clever citizens took to the internet and "debunked" the "myth", saying it couldn't possibly work.
The basic argument goes like this: ADH is most effective at a slightly basic pH.6 But the human stomach, where supposed yeast ADH metabolism of ethanol would occur, has a pH around 1.5 to 3.5 (and that's really acidic).
While I get the argument that's being made, science has already shown in multiple instances that ADH not only already exists in the stomach lining, but that it acts to breakdown ethanol in the stomach.3, 7, 8
Those who argue that ADH won't work in the stomach's acidic environment reference one paper on liver ADH and another paper that looked at yeast ADH in an acidic environment, but only after 24 hours.
Here's where understanding alcohol metabolism comes back into play. It doesn't really matter what happens to ADH after a day or even an hour in the stomach. Alcohol absorbs very quickly, so any effect from yeast ADH would have to happen in a matter of minutes to be effective.
Can yeast make a difference in that amount of time? I did a quick experiment to find out.
...
My conclusions seem to match up with what has been observed in actual human studies. Dr. Joseph Owades, the biochemist and brewing expert Jim Koch credited with the yeast trick in the first place, actually patented the technique and includes in his patent application graphs that show the effect of yeast on blood alcohol levels.
...
If you're trying to avoid a hangover this trick may not be for you. Many researchers blame the byproducts of ethanol metabolism, acetaldehyde and acetate, and not just ethanol itself, for hangovers. The ADH in yeast only helps you digest ethanol into acetaldehyde and acetate and doesn't provide for further digestion of those two toxins.10
Same goes for the Asian "glow." Researchers believe that the cause behind the Asian glow also has to do with acetaldehyde in the blood stream, not ethanol, so once again, the yeast trick might keep you from getting drunk, but probably won't do anything to help with flushing (www.seriouseats.com/2014/05/can-yeast-keep-you-from-getting-drink-jim-koch-alcohol-trick-how-alcohol-is-digested.html).

Does Baker's Yeast Really Prevent You From Getting Drunk?
This question came to light over a much-ballyhooed excerpt from Aaron Goldfarb’s Esquire interview with Jim Koch, founder and CEO of Boston Beer Company, makers of the Samuel Adams line of craft lagers and ales.
In the article, “How To Drink All Night Without Getting Drunk,” Goldfarb quotes Koch’s strategy of pre-treating himself with grocery store-bought, Fleischmann’s active dry baker’s yeast. Koch claims that one teaspoon of dry yeast per anticipated serving of beer (mixed with yogurt for palatability), “will mitigate – not eliminate – the effects of alcohol.” Esquire writers tried to reproduce the effect, admittedly non-scientifically, and pretty much unsuccessfully.
Nevertheless, the April 24th story was cited in several newspapers and magazines, and went viral on social media, with 29,000 Facebook shares, over 1,000 tweets, nearly 400 comments, and an entire Reddit r/beer thread.
Why?
Well, Koch is no humbug in beer circles. Although preceded by Fritz Maytag who resuscitated San Francisco’s Anchor Steam Brewing in 1965, Koch (pronounced “cook”) is arguably one of the major forces in the resurgence of craft lagers and ales.
So, when Jim Koch speaks, people listen (www.forbes.com/sites/davidkroll/2014/05/19/does-bakers-yeast-really-prevent-you-from-getting-drunk/#1fcc4ad72e55).

Koch’s scientific rationale does have a notable pedigree. The idea was developed by the late Ph.D. biochemist, Joseph L. Owades, whose brewing expertise preceded that of Koch and Maytag. Owades is best known for his pre-Miller Lite development of the first light beer and rose to vice president of Brooklyn-based Rheingold, my dad’s favorite beer and sponsor of the New York Mets in the 1960s and 1970s.
A few years before passing away in 2005, “Dr. Joe” was granted a U.S. patent (#6,284,244) for the method of prior or concomitant ingestion of baker’s yeast as “a process for lowering of blood alcohol (i.e. ethyl alcohol) levels in humans after they imbibe alcoholic beverages such as beer, wine or distilled spirits.”
Alcohol dehydrogenase, or ADH, is an enzyme in yeast that produces alcohol. In the brewing process, that’s how we get alcohol from the sugars that are released from the malted barley and other grains. But it can also work in the reverse direction to metabolize the alcohol back into its precursor, acetaldehyde. Yeast also have multiple forms of the enzyme the predominate in one direction or another. That’s been a little confusing to folks who’ve been commenting on the topic around the Web.
Owades claims that baker’s yeast contains enough ADH to act in the stomach to catalyze that reverse reaction. That conversion of alcohol to acetaldehyde is the theoretical reason why ingesting yeast might lower one’s exposure to alcohol.
Where are the data?
Owades’ patent application cites experimentation with eight human subjects who quickly ingested various alcoholic beverages with and without the baker’s or vintner’s yeast pretreatment. He then measured blood alcohol levels for then next three-and-a-half hours afterward using a breath analyzer. In the data presented, Owades claims that the blood levels of ethanol over time were 20-38% lower when subjects ingested yeast at the time of drinking the alcoholic beverage (www.forbes.com/sites/davidkroll/2014/05/19/does-bakers-yeast-really-prevent-you-from-getting-drunk/#1fcc4ad72e55).

Mediating the effects of alcohol consumption by orally administering active dry yeast
US 6284244 B1
SAMENVATTING
Mediating the effects of alcohol consumption by orally administering an active dry yeast containing alcohol dehydrogenase to a person prior to or simultaneously with consumption of an alcohol-containing beverage to oxidize a portion of the alcohol while it is still in the stomach of the person is described.
Consumption of alcoholic beverages in moderate amounts is an accepted societal practice. Additionally, consumption of alcoholic beverages in moderate amounts is considered to provide some health benefits in terms of reduced stress and incidence of heart attack. Consumption of alcoholic beverages in moderate amounts also is considered by many people to enhance the flavor and enjoyment of food. However, even moderate social drinkers can be affected by alcohol. Ethyl alcohol (CH3CH2OH) is a major purpose for the consumption of alcoholic beverages. When such beverages are consumed, the alcohol enters the stomach and is soon transported to the small intestine. From here the alcohol enters the blood stream via the portal vein and goes to the liver. Here, a portion of the alcohol is oxidized to acetaldehyde by the enzyme alcohol dehydrogenase. The unoxidized alcohol goes to every part of the body through the general circulation. This alcohol, which has free access to every cell in the body, exerts an influence on the central nervous system and the brain. These effects are well known. Operation of a motor vehicle is considered illegal if the level of alcohol in the blood (blood alcohol level) is above 0.1% (in some states) or 0.08% (in other states). Because alcohol diffuses into every cell in the body freely, the blood alcohol level may be measured in the breath as well as in the blood. The acetaldehyde produced is further oxidized almost instantaneously to acetate which enters the pathways of general metabolism. Acetaldehyde and acetate have no effect on the nervous system or the brain. Continued circulation through the liver eventually removes all the alcohol.
It has been found that ingesting active dry bakers yeast (the yeast most readily available commercially) or brewers, vintners or distillers yeast, just before, or during, the drinking of an alcoholic beverage, oxidizes a portion of the alcohol while still in the stomach, which results in a lower peak blood alcohol level, and also a lesser area under the curve of a plot of blood alcohol level vs. time. The action of the alcohol dehydrogenase on the alcohol is only in the stomach, so the alcohol dehydrogenase source must be ingested while the alcoholic beverage is still in the stomach. It will have no effect once the alcohol has left the stomach and entered the bloodstream, because the enzyme is destroyed by the acidity and proteolytic action in the stomach.
What is claimed is:
1. A method of mediating the effect of alcohol consumption by a person which consista essentially of orally administering active dry yeast containing alcohol dehydrogenase to said person prior to or simultaneously with consumption of an alcohol-containing beverage, whereby to oxidize a portion of the alcohol while still in the stomach of said person.
2. A method according to claim 1, wherein said active dry yeast is administered in a dose of from 0.5 to 10 grams.
3. A method according to claim 1, wherein said active dry yeast is selected from the group consisting of active yeast, active dry brewers yeast, active dry vintners yeast, and active dry distillers yeast.
4. A method according to claim 1, wherein said active dry yeast is administered in tablet, caplet or capsule form.
5. A method according to claim 1, wherein said active dry yeast is consumed as a powder, paste or liquid. (www.google.com/patents/US6284244)

“My main question is, ‘Has anyone ever repeated Owades experiments?,’” asks Robert A. Sclafani, Ph.D., professor of biochemistry and molecular biology graduate program director at the University of Colorado Denver’s School of Medicine. Sclafani also leverages his yeast biochemistry expertise as the principal of Brewgenes Consulting Co., a brewing and biotechnology consulting service. (Disclosure: I did my postdoctoral research between 1990 and 1992 in departments at Colorado that were affiliated with Dr. Sclafani’s department.) (www.forbes.com/sites/davidkroll/2014/05/19/does-bakers-yeast-really-prevent-you-from-getting-drunk/#1fcc4ad72e55).

Indeed, Owades’ experiments in the patent application have never been published in a peer-reviewed journal. In fact, I doubt that any journal reviewers would let the work be published as presented.
First of all, the earliest breathalyzer reading, and highest alcohol concentration, is at 10 minutes. But alcohol remaining in the mouth can make this appear artificially high. Ideally, breath should best be measured beginning at 20 minutes after the last drink. Also, we don’t know how many times the analysis was repeated at each time. Finally, Owades mixed the types of alcoholic drinks, subjects, and even the yeast, used across only eight subjects.
But Owades convinced himself enough to trademark the name “Prequel” for the packaging of yeast in capsules for the purpose of reducing the effects of alcoholic beverages. The product was never marketed, in part because of the obvious liability issues that would be incurred.
The acid test
But for this strategy to work, the yeast must be able to stay active in the stomach. About 70% of ingested alcohol gets absorbed into the bloodstream in the stomach. Many other beneficial chemicals and other nutrients in our foods get absorbed later in the small intestines.
Sclafani breaks down the critical question of whether the yeast can not only survive in stomach acid, but whether the ADH will still work.
In an email interview, Sclafani said, “The pH of the stomach varies from 2-4 but will be at 2 when you are eating. My guess is that the combination of pH 2 and active digestive enzymes will make it unlikely that yeast ADH can work well (its pH optimum is about 8.6).”
Even Owades acknowledged this point in the body of his patent application: “Since the ingested alcohol dehydrogenase does not long survive in the acidity of and in the presence of the proteolytic enzymes in the stomach, the ingested alcohol dehydrogenase has no effect beyond the stomach.”
The one caveat is that the ADH is not just floating around naked inside the stomach (although Owades did include the use of pure, naked ADH in one of his patent claims). It’s encased in yeast, which has its own process for regulating pH inside the cell. The pH of beer and wine is between 3 and 4, so some yeasts can survive in somewhat acidic conditions.
But no one has done the experiments to determine how much alcohol yeast could metabolize under these pH and alcoholic beverage conditions. If I still had my laboratory, I’m sure I could wrassle an undergraduate research student into doing this project. Perhaps Dr. Sclafani might have a rotating graduate student interested in this topic.
In fact, Sclafani even gave us part of the experimental design.
“Some distiller’s yeast can grow up to almost 20% EtOH [ethanol] as they have amplification of ADH genes. He does not say whether distillers yeast worked better as you would expect.”
One of the major reasons that excessive drinking can cause hangovers is because of the acetaldehyde produced by alcohol metabolism. So even if taking yeast to lower alcohol levels worked, you’d possibly end up with more hangover effects.
Sclafani explains, “You also need to have ALDH [aldehyde dehydrogenase] working or you will get to much acetaldehyde which is a carcinogen and will make you sick (for example, many asians are missing ALDH and get “flushing” when they drink alcohol).” (www.forbes.com/sites/davidkroll/2014/05/19/does-bakers-yeast-really-prevent-you-from-getting-drunk/2/#154fe48d1e90)

Indeed, acetaldehyde is a nasty chemical. You’ve likely smelled it if you’ve detected a sort of green apple odor on the breath of people drinking. If any other food product led to hangovers and cancer as alcohol does, consumers and food safety advocates would be up in arms. (Imagine if you drank the same amount of soda and had a throbbing headache, nausea, and electrolyte imbalances the next morning.) During drinking, acetaldehyde causes blood vessels to become dilated and “leaky,” disrupting how fluid is distributed in the body. Because it concentrates in saliva at a higher concentration than blood, acetaldehyde is a known cause of oral and esophageal cancers after years of chronic drinking.
The take-home points
Ingesting baker’s yeast prior to drinking is unlikely to reduce blood alcohol levels or make you less intoxicated. Even if this approach worked, the effect of drinking four drinks might be the same as drinking three drinks. In the case of Jim Koch, he likely drinks with enough frequency that his body his increased levels of one of the enzymes that metabolizes alcohol. (Several Redditors maintain that they have seen Koch intoxicated yet still give lucid presentations. Of course, take Reddit comments as such. Beer enthusiasts who would attend events featuring Koch were likely under the influence as well.)
So, if you don’t want to get drunk, drink 20-38% less. Or drink the same amounts but choose beverages with lower alcohol concentrations. That’s less glamorous and clever than a folk remedy suggested by a brewing giant, but it’s definitely going to produce the desired outcome.
And about the only thing to help with hangovers is to drink less, stay hydrated while drinking (alcohol is a diuretic), possibly take B vitamins before, during, and after drinking, and replenish your electrolytes (some people use sports drinks but recovering alcoholic, musician Jason Isbell, used pediatric electrolyte solutions during his drinking days.) (www.forbes.com/sites/davidkroll/2014/05/19/does-bakers-yeast-really-prevent-you-from-getting-drunk/3/#eb20ce05ebb5).

Biochemistry. 2014 Sep 16; 53(36): 5791–5803.
Published online 2014 Aug 26. doi:  10.1021/bi5006442
PMCID: PMC4165444
Yeast Alcohol Dehydrogenase Structure and Catalysis
Savarimuthu Baskar Raj,† S. Ramaswamy,‡ and Bryce V. Plapp*
Yeast (Saccharomyces cerevisiae) alcohol dehydrogenase I (ADH1) is the constitutive enzyme that reduces acetaldehyde to ethanol during the fermentation of glucose. ADH1 is a homotetramer of subunits with 347 amino acid residues. A structure for ADH1 was determined by X-ray crystallography at 2.4 Å resolution. The asymmetric unit contains four different subunits, arranged as similar dimers named AB and CD. The unit cell contains two different tetramers made up of “back-to-back” dimers, AB:AB and CD:CD. The A and C subunits in each dimer are structurally similar, with a closed conformation, bound coenzyme, and the oxygen of 2,2,2-trifluoroethanol ligated to the catalytic zinc in the classical tetrahedral coordination with Cys-43, Cys-153, and His-66. In contrast, the B and D subunits have an open conformation with no bound coenzyme, and the catalytic zinc has an alternative, inverted coordination with Cys-43, Cys-153, His-66, and the carboxylate of Glu-67. The asymmetry in the dimeric subunits of the tetramer provides two structures that appear to be relevant for the catalytic mechanism. The alternative coordination of the zinc may represent an intermediate in the mechanism of displacement of the zinc-bound water with alcohol or aldehyde substrates. Substitution of Glu-67 with Gln-67 decreases the catalytic efficiency by 100-fold. Previous studies of structural modeling, evolutionary relationships, substrate specificity, chemical modification, and site-directed mutagenesis are interpreted more fully with the three-dimensional structure.... Yeast ADH1 was one of the first enzymes to be crystallized.5 Thin, hexagonal crystals were also found in anaerobically grown yeast, apparently with a tetrahedral arrangement of subunits in the P312 space group.12,13 Crystals that diffracted well for X-ray crystallography were reported previously,14,15 and we collected many data sets; however, most crystals were twinned, and a structure could not be determined by molecular replacement (despite the availability of several ADH structures) or by multiple isomorphous replacement. We found one, only partially twinned, crystal with different cell dimensions and determined the structure by molecular replacement using the structure of the tetrameric Pseudomonas aeruginosa ADH.16 The structure of yeast ADH1 now permits comparisons with other ADHs and a better understanding of previous studies of ADH1 (www.ncbi.nlm.nih.gov/pmc/articles/PMC4165444/).

NPR tests Jim Koch's method of eating yeast to keep you from getting drunk
Discussion in 'Beer News' started by CASK1, Jul 11, 2014.
A recent thread in this forum discussed Jim Koch's (of BBC) method of avoiding intoxication by consuming yeast before drinking beer. The staff at NPR took it upon themselves to test his method. Interesting read (www.beeradvocate.com/community/threads/npr-tests-jim-kochs-method-of-eating-yeast-to-keep-you-from-getting-drunk.193821/).

Alcohol Test: Does Eating Yeast Keep You From Getting Drunk?
July 10, 20144:33 PM ET
And as we get older, we're warier of that third or fourth glass. The consequences of too much alcohol — the drowsiness, the confusion and the wobbling — are a bigger hindrance. And let's face it: A hangover at 36 isn't the same as one at 22.
So when we came across a tip in Esquire for staving off intoxication, we perked up. You mean I might be able to have another glass of pinot noir or a third IPA without getting as loopy? Tell me more.
Jim Koch is a professional drinker. As the founder and brewer of Sam Adams, Koch tastes every batch of beer Boston Beer Co. makes before it leaves the brewery. This involves a lot of sipping, sometimes well before noon.
To keep his mind sharp and taste buds savvy through all those lagers and ales, Koch has a secret: He mixes a teaspoon of baker's yeast with a small amount of food — usually yogurt — and gulps it down immediately before laying into a pint.
"I've been doing this for 10 years," Koch tells The Salt. "I experimented with this in the beginning with portions until I got it down."
Yeast are microscopic, single-celled fungi, and Koch's explanation is that they break down some of the alcohol in the stomach before it gets absorbed in the bloodstream. "It mitigates the effect of alcohol," he says. In other words, it allows him to drink at 9 a.m. and go right back to running his company.
Now, Koch didn't make up this trick. He learned it from biochemist and legendary brewer Joseph Owades, who helped to develop low-calorie, light beers.
And it sounds like it might work. Yeast has an enzyme, just like our own livers and stomach linings, that can break down alcohol. (It's called alcohol dehydrogenase for all you biochemistry boffins.)
But we were dubious. Yeast makes alcohol from sugar. If it were good at degrading it, wouldn't it eat up all the ethanol in wine and beer?
Though there's plenty of research showing that food in the stomach slows the absorption of alcohol into the bloodstream, we couldn't find anything on yeast doing the same thing.
And as science writer Adam Rogers notes in his new book, Proof: The Science of Booze, there's been little research in general devoted to the question of how to temper the effects of alcohol while drinking.
If ever there was an excuse for some (pseudo) science — not to mention some on-the-job tippling — this was it. We decided to test Koch's alcohol mitigation technique on ourselves: one 37-year-old female weighing 125 pounds, one 35-year-old male weighing 152 pounds and one 34-year-old female weighing 125 pounds.
...
"Yeast can degrade ethanol," says microbiologist Benjamin Tu of the University of Texas Southwestern Medical Center. "But they love other sugars — glucose, maltose — more. When those sugars are around, the cells turn off the genes needed for alcohol degradation."
Many beers contain some leftover sugars that don't get fermented. Yogurt has sugars, too. So if Koch is eating the yeast with yogurt, that offers the fungi something more tempting than alcohol.
Plus, Tu says, the yeast most likely won't have time to degrade the alcohol before our digestive tracts absorb it. "I think the exposure time of the alcohol to the yeast is too low," he says. "Any effect of the yeast [on BAC] will be marginal."
Neurobiologist George Koob, who directs the National Institute on Alcohol Abuse and Alcoholism, agrees with Tu's assessment.
"[Koch's technique] falls more in the 'urban legend' category than into science," Koob tells The Salt. "Basically we think that probably yeast ... is delaying the absorption of alcohol because any foodstuff or anything you take that occupies the stomach lining is going to impede the absorption of alcohol." (www.npr.org/sections/thesalt/2014/07/10/327854051/alcohol-test-does-eating-yeast-keep-you-from-getting-drunk)

WEDNESDAY, SEPTEMBER 23, 2015
You can't stop from getting drunk by eating yeast before drinking
...
Via the Chemistry Reddit, an article from Esquire that is likely to be really, really wrong (emphasis mine): 
Koch told me that for years he has swallowed your standard Fleischmann's dry yeast before he drinks, stirring the white powdery substance in with some yogurt to make it more palatable. 
"One teaspoon per beer, right before you start drinking." 
He'd learned the trick from his good friend "Dr. Joe," a craft beer legend in his own right. Educated at Harvard with a troika of degrees (a BA, a JD, and an MBA), Koch is no slouch, but the late-Joseph Owades was a flat-out genius.
...
I think this is wildly wrong. Almost all enzymes are temperature- and pH-dependent. That is to say, they work best (transforming chemical starting materials to product, or vice versa) when they are in a certain pH range and temperature. I find it unlikely that yeast alcohol dehydrogenase works well in the highly acidic environment of the stomach. Also, why would the enzymes in the stomach (pepsin, etc.) fail to digest the yeast?
Note for people who find this via Google: this advice is almost certainly wrong. Dr. Owades was probably incorrect; if you take yeast with your beer, it will probably have no effect on your blood alcohol level (http://chemjobber.blogspot.nl/2015/09/you-cant-stop-from-getting-drunk-by.html).

De bewering dat je veel bier kunt drinken zonder dronken te worden is afkomstig van Jim Koch. Deze Amerikaan geldt als een autoriteit op het gebied van bier en is mede-oprichter van de Boston Beer Company. Mogelijk heb je hem wel eens gezien in biercommercials van Samuel Adams.
Jim Koch kwam in contact met  bierbrouwer Joseph Owades, die Koch vertelde over de werking van droge actieve gist. Deze gist bevat het enzym alcoholdehydrogenase (ADH). Net als je eigen lever breekt dit enzym alcohol af. Het enzym zet alcohol om in koolstof, waterstof en zuurstof. Dus zo redeneerde Owades, als je maar zorgt dat je voldoende van dit enzym in je maag hebt, kun je bier drinken zonder dat je dronken wordt. Nou ja, niet helemaal. Het effect van alcohol zal niet helemaal nul zijn, want er zal altijd iets alcohol in je bloedbaan terecht komen als het in je maag terecht komt, maar de werking wordt zeker sterk gereduceerd.
Jim Koch zweert bij de methode. Als hij onderweg is naar een festival eet hij een bekertje yoghurt met droge gist. Voor elk glas bier dat hij denkt te gaan drinken eet hij een theelepel gist. Koch kan zo heel veel bieren proeven en tot het eind toe zonder dubbele tong zijn deskundige oordeel geven over de bieren.
Joseph Owades kan het niet meer vertellen en uitleggen. Hij was zo overtuigd van zijn gelijk dat hij voor zijn dood in 2005 een pil heeft gepatenteerd met ADH, die de alcohol afbreekt. Als het echt zou werken, waarom is het dan zo weinig bekend? En zijn er bierliefhebbers die ervaring hebben met deze methode? Zijn er medici die dit kunnen bevestigen of ontkennen? En zitten we überhaupt op zo’n pil te wachten? Reageer … 
Jan Beekaa  2 jaar geleden
Reeds uitgebreid 'gedebunked' http://www.seriouseats.com/201...

What did I learn?
While it seems that yeast ADH does help to decrease alcohol levels
it's probably not that much.
and it takes a few minutes, during which time some alcohol will inevitably make it into the blood.
My conclusions seem to match up with what has been observed in actual human studies. Dr. Joseph Owades, the biochemist and brewing expert Jim Koch credited with the yeast trick in the first place, actually patented the technique and includes in his patent application graphs that show the effect of yeast on blood alcohol levels.
Let's first talk about who shouldn't use the yeast trick.
If you're allergic to alcohol, know that the ADH in yeast will not fully metabolize alcohol before it makes it into your bloodstream, so don't do this, because you will inevitably react to the alcohol that's present.
If you think you might be allergic to alcohol you may actually be sensitive to other compounds found in alcoholic beverages, not ethanol itself, so the yeast trick will do nothing for you.9
If you're trying to avoid a hangover this trick may not be for you. Many researchers blame the byproducts of ethanol metabolism, acetaldehyde and acetate, and not just ethanol itself, for hangovers. The ADH in yeast only helps you digest ethanol into acetaldehyde and acetate and doesn't provide for further digestion of those two toxins.10
Same goes for the Asian "glow." Researchers believe that the cause behind the Asian glow also has to do with acetaldehyde in the blood stream, not ethanol, so once again, the yeast trick might keep you from getting drunk, but probably won't do anything to help with flushing (www.seriouseats.com/2014/05/can-yeast-keep-you-from-getting-drink-jim-koch-alcohol-trick-how-alcohol-is-digested.html).

Werkt het nu wel of niet? Het lijkt mij van niet... maar misschien wel een beetje? 

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