Coby
moleculeoftheday
Posts by this author
March 6, 2008
Well, it finally happened. I made it almost two years, but I repeated a molecule for what I think is the first time.
Hooray! Any pressure to be original is off! Here's the first of many best-of posts to come!
One thing I've done from time to time is crude experimentation on a recent household…
March 6, 2008
The series of Breaking Bad chemicals continues (spoilers inside). Previously: phosphine, mercury fulminate. Today: hydrogen fluoride.
HF is just that, H-F, or a hydrogen bound to a fluorine. All the other acids in this group - HCl, HBr, HI - are gases. What we call "hydrochloric acid" is HCl in…
March 5, 2008
As a commenter surmised in my entry on phosphine, I really like Breaking Bad. The main character is a chemist, and the writers have done a good job of working a lot of chemical tidbits into the mix (even ones not about methamphetamine, which drives much of the plot).
Now through Friday: molecules…
March 3, 2008
Butyric acid has been covered obliquely before - it's part of the nice-smelling amyl butyrate (which is eau de Juicy Fruit, pretty much). On its own, though, it's a foul vomit-smelling liquid (the Wikipedia article, however, notes that some intrepid chemist tasted it and reported it had a sweetish…
February 29, 2008
Lots of chatter in the news today about finding ricin in a Vegas hotel room.
Image of PDB ID 2AAI from Wikipedia
Ricin works by inhibiting protein synthesis at the ribosomal level. This is a well-known method of killing something, and one on which many antibiotics work.
You'll note this looks…
February 27, 2008
Dutasteride is of the same class of drug as Propecia and Proscar - the so-called 5-alpha-reductase inhbitors. These inhibit the enzyme of this name from converting testosterone into dihydrotestosterone.
Interestingly, the class is useful for both prostate hyperplasia (proscar) and hair loss (…
February 25, 2008
Longtime readers will know I like big dye molecules.
Once you get to the size of a phthalocyanine - a little over 1 nm across in any dimension (one of those bonds is about 0.15nm) - weird stuff happens. This explains, in part, G-quadruplexes and liquid crystals,
A friend of mine that made…
February 22, 2008
All of life links up biomolecules effortlessly, from the august readers of this blog, to the humble bacteria that colonize the half-eaten food on their desks. It makes it frustrating for scientists who are trying to synthesize them. We have methods, but they're inefficient. (It gets even worse for…
February 20, 2008
Yesterday, I discussed a laxative drug that works by drawing water into the intestines (and introduced you to a helpful chart to aid description of particularly ineffable bowel movements).
Here is a drug that works on the same principle, but indirectly - it induces your intestines to secrete ions…
February 19, 2008
Whether it is constipation or diarrhea, irregularities in bowel movements on some level all relate to the balance of fluid in the intestines. Fiber doesn't just add bulk to feces, it holds onto water. If you go all Linus Pauling and take way too much vitamin C, you'll get diarrhea - the prodigous…
February 15, 2008
Aflatoxin is a toxin produced by certain funguses that acts on the liver:
The asperilligus strains that express aflatoxins (this is a broad class of molecules; the one above is aflatoxin B1) grow on lots of different crops. Your peanut butter certainly contains some. Fortunately, people are one of…
February 14, 2008
Biotin is just a vitamin to most of us. To a lot of biologists, though, it plays the unlikely role of some of the strongest glue around.
There are proteins known as avidins that bind biotin so strongly that it's pretty much irreversible. If you stick biotin on something you're interested in, and…
February 12, 2008
I have a lot of sympathy for graphic designers. For every one preaching to you about how you can't possibly appreciate whitespace on the same level she does, there's nine out there slogging away doing honest work. The ones who are just trying to convince the guy with the mattress store not to put…
February 8, 2008
Certain derivatives of coumarin called psoralens have the effect of sensitizing you to the sun. This can be useful for treating certain skin conditions with psoralen plus a little UV lights. It can also get you really, really tan. The downside of psoralen+UV is that it's riskier skin cancer-wise…
February 5, 2008
As I've mentioned before, I'm a booster for DNA G-quadruplexes as drug targets. While telomeres might not be the best target, there are lots of potentially oncogenically relevant quadruplexes. Here is the only quadruplex-targeting antineoplastic that's made it into the clinic that I know of.…
February 4, 2008
Ammonia, or NH3, is a mildly toxic gas (but not that bad - you use it in metabolism). Go down one, though, and you get more lavishly toxic.
Phosphine, or PH3, is much more toxic (go down another, to arsine, and you've got another toxic beastie). Phosphine is used in fumigation for this very reason…
February 1, 2008
125 years ago, a physiologist named Sidney Ringer discovered that a solution of saline prepared by his assistant seemed to keep excised rat hearts beating longer than normal saline.
It turns out this is because the assistant was a lazy slob and used London tap water instead of distilled. Good thing…
January 30, 2008
This one always shocks people the first time they hear it. Have you ever seen "carmine" on an ingredients label of some food in the red-purple color family? Yeah, you're eating bugs.
Carminic acid is extracted from the shells of certain insects.And you're not necessarily safe if it doesn't say "…
January 29, 2008
After this weekend's discussion of chirality in advertising, I figured I'd post an interesting, more rigorous example of chirality. Most chiral (left- or right-handed)molecules have "asymmetric" carbons, or ones with all different things attached.
Helicene, by contrast, has none. However, it's got…
January 26, 2008
Even in cosmetics.
The scientific tour de force doesn't stop there; they also give you lessons on deuterium oxide, fullerenes, and liquid crystals.
The deuterium oxide thing is puzzling - another cosmetics company purports to sell spritzers of D2O. It's almost enough to make you buy some just to…
January 25, 2008
The previous entry on raspberry ketones got me thinking about supplements in general. For the most part they don't cause people problems - which is pretty remarkable, considering a lot of them do have real druglike molecules in them. Most people are taking these completely unsupervised, with only a…
January 23, 2008
I have to admit, I am a sucker for common names. Why would you grab a bottle of mercury (II) chloride when you could get some "corrosive sublimate"? 3-methylindole? No thanks, give me skatole (named for its smell!). Methyl tert-butyl ketone? Pinacolone (which, sadly, smells like mint). 1,8-bis(…
January 21, 2008
Everyone knows that many organic solvents won't mix with water (or, more generally, some polar solvents won't mix with some nonpolar solvents). What you might not know is that some highly fluorinated liquids aren't very polar at all, but they won't dissolve in water or many organics.
In fact, you…
January 17, 2008
Lead and chromium (VI) - you can't do much better for toxicity.
The lead (II) salt of chromium (VI) oxide gives a vivid yellow. Before organic dye technology became robust, we were stuck with metal salts for color. This means metals. Unfortunately, there are more toxic metals than nontoxic metals,…
January 15, 2008
A few months ago, a group published a report that this polyamine was an effective quadruplex ligand, inducing senescence of cancer cells.
It's perhaps unsurprising that this works. I've previously covered Telomestatin (more selective) and TMPyP4 (less selective), but man, just a big charged chain…
January 14, 2008
I love the story of valproate. About fifty years ago, an investigator was using a fatty carboxylic acid as a delivery vehicle for antiseizure medications. He looked at it alone in controls and, lo and behold, it was a drug on its own:
It's a humbling reminder to anyone who's ever designed a drug:…
December 27, 2007
Everyone by now has tried products like OxiClean, or detergents with "oxygen bleach." Rather than sodium hypochlorite, which is found in regular bleach, they've got sodium percarbonate, which is actually a mixed crystal of sodium carbonate (the old-timey name of which is "washing soda") and…
December 19, 2007
But if you've never read it, check out Can a Biologist Fix a Radio?
December 18, 2007
Mutual funds are such a common instrument, it's hard to imagine they were once a novel concept. In 1924, $10M were invested in US mutual funds. In 1964, $35B were invested. Skip ahead to today and the number is $12T - that's $12 x 1012. Such logarithmic growth is due to boosters like Jack Dreyfus (…
December 14, 2007
Making biomolecules is tricky - getting a reasonable quantity of whatever DNA or protein you're after can take what seems like heroic efforts. You're made acutely aware of the fact that the humblest bacterium does this without breaking a sweat. Protecting and activating groups are needed, like DMT…