The Mystery Molecule Page: 2005


Creatinine will be the focus of our December meeting but this molecule has been proposed as a better marker of glomerular filtration rate. Can you guess what it is?

Cystatin C
This small protease inhibitor is produced by all nucelated cells at a constant rate and it is freely filtered by the renal glomerulus. Many studies have shown that it may be more accurate than creatinine as a marker of renal insufficiency (because it is much less affected by age, gender and muscle mass).


This molecule will be the topic of conversation at our November meeting. Can you guess what it is?

Illicit use of this drug, also present as an endogenous metabolite in the human brain, has been associated with “date rape” because the drug rapidly induces drowsiness and euphoria and, later, amnesia.


This molecule’s over-the-counter availability was recently the subject of a controversial FDA decision. Can you guess what it is?

“Morning after” emergency contraception (discussed last week) was originally two doses of estrogen/progesterone but the side effects associated with the high estrogen dose led to “Plan B” which is this progesterone agent only. The mechanism of action is unclear but may involve postponing ovulation or creating an out-of-phase endometrium inhospitable to implantation.




This molecule reduces the euphoric feeling associated with alcohol and may be used to treat alcoholism. Can you guess what it is?

This non-addictive opiate has been used to treat heroin addiction for many years but was recently discovered to block the craving for alcohol. While opiate receptor blockade may be involved, the precise mechanism is unknown.


This molecule was discussed during the plenary session at last month’s AACC meeting dealing with pharmacogenomics . Can you guess what it is?

In his plenary lecture, Dr. Richard Weinshilboum described how testing for thiopurine methyl transferase can help predict toxicity in patients being treated with this anti-metabolite (or the related drug, azathoprine).



This molecule, found in an alcoholic drink, may have caused Paul Gauguin to see strange colors. Can you guess what it is?

This is the active ingredient in absinthe, a once-popular beverage derived from wormwood leaves. It was banned because of toxicity (including hallucinations and convulsions). Pastis is a similar product (but without the wormwood).


This molecule (with antigenic sites colored and the active site indicated by the arrow) was discussed by Dr. Tom Stamey at our May meeting in San Mateo. Can you guess what it is?

Prostate Specific Antigen
This famous tumor marker is actually a serine protease. Protease inhibitors (especially anti-chymotrypsin) bait the active site and snap a trap, causing the inactivated enzyme to be bound to the inhibitor. (This is the reason for “bound” and “free” PSA.) 


This molecule was mentioned by Dr. James Betts at last month’s meeting sponsored with the American Chemical Society as one of the first synthetic anabolic steroids. Can you guess what it is?

This synthetic steroid is primarily used to treat endometriosis (ectopic growth of uterine mucosa) in women but it is also used illegally by athletes to increase their lean muscle mass.



This molecule is referred to in Rose Romeo's minutes from last month's CLTAC meeting (see new feature of webpage). Can you guess what it is?

Hepatitis B surface antigen
The envelope of Hepatitis B virus contains this large protein and infected hepatocytes synthesize large amounts of it (seen here as empty tubular structures by scanning electron microscopy). Rose’s minutes included comments about new legislation to help the state’s Public Health labs deal with infectious diseases including “viral hepatitis”.


At the February, 2005


nterleukin-4 (IL-4)
Allergic disease may result from an imbalance in the numbers of Th1/Th2 CD4 (helper T) cells. IL-4 promotes development of the Th2 phenotype with increased IgE production. This may occur because of reduced exposure to bacteria and other pathogens (the "hygiene hypothesis") or genetic predisposition to IL-4 production.


NoCA AACC meeting, this molecule was blamed for promoting allergic disease (see on-line version under Past Meetings). Can you guess what it is?


This molecule is eclipsing its rivals for market share in the competitive field of artificial sweeteners. Can you guess what it is?

The tagline on packets of "Splenda" say "Made from sugar so it tastes like sugar." Replacing three hydroxyls in sucrose with chloride must make it hard to metabolize. And manufacturers love sucralose because it has a longer shelf-life than aspartame ("Equal") and saccharin ("Sweet'N Low"). Hope your Valentine's Day was "real" sweet!


This molecule may have been served in seafood chowder to Viktor Yushchenko, the new president of Ukraine. Can you guess what it is?

2,3,7,8-tetrachlorodibenzodioxin to be exact - the most toxic of the over 200 molecules called dioxins. They all have two benzene rings joined by oxygen molecules (blue). TCDD has four chlorine molecules (yellow) and was a contaminant in the infamous Agent Orange, ironically Mr. Yushchenko's campaign color.

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