Molecules: You'd better learn to live with them.
As far as I know, selenocysteine is the only reason you need selenium in your diet (which you almost certainly get enough of; the requirement is vanishingly small, <100 micrograms/day). It is a member of the same group as oxygen. As you go down a group, things change in subtle ways. Sulfur is a less-electronegative, bigger, more polarizable, more nucleophilic, stinkier oxygen. Similarly, selenium is all these things, but more so!
It is the nucleophilicity that is so important; it is found in the amino acid selenocysteine - that is, the selenium analogue of the sulfur amino acid cysteine (or the oxygen amino acid serine).
Selenocysteine plays a role in thioredoxin reductase, the reaction of which with curcumin may have chemotherapeutic applications.
Physical Science
Medicine & Health
Comments
One of the methods for offsetting selenium toxicity is exposure to arsenic, however, exposure to selenium also offsets arsenic toxicity. I guess two wrongs do make a right.
http://www.jstor.org/pss/3428469
Posted by: As You Lean | April 10, 2008 6:48 PM
Good timing on this post as FDA just yanked a dietary supplement with 200-400X the recommended selenium content. The website for the product (Total Body Formula) is down so I don't know what form of selenium was in the supplement.
Posted by: Abel Pharmboy | April 11, 2008 11:30 AM