The World of Isoprenes

While I was poking around the web this morning looking for some decent metabolic maps, I came upon this really excellent map of isoprenoid biosynthesis. I've seen a couple maps of similar scope, but I like how this one highlights the metabolites that people are likely to be familiar with (essential oils, vitamins) and shows how the isoprene subunit is the root of synthesis of so many disparate biological products. Isoprenes aren't just for plants - the retinal that functionalizes rhodopsin to enable us to perceive light and the cholesterol that forms the basis for the synthesis of the steroid hormones are both isoprene derivatives.

That map was put together by a real visionary, Dr. Donald Nicholson. Awardee of the ridiculously prestigious "Special Life Member" status in the IUBMB, his minimaps and animaps are changing the way people think about (and teach!) the chemistry of metabolism. His stated goal: "To Make Metabolism Meaningful, Wonderful and FUN." Bravo, sir!

For the stressed, the body-builders, the guys and gals out there who feel the effects of steroids every day: a fantastic map of steroidogenesis, courtesy Wikipedia. Bet you're glad you learned organic chemistry, right? It's never too late!

Majickal Elixirs

I don't have to go much farther than my Google Search History to find inspiration for something to document - I read Wikipedia like regular people read the Sports section. While most of my recent searches are stupid and pedestrian ("How long until doxycycline works?", I wondered at 12:42pm), there are a few good ones in here. Today's topic: 'elixir terpin hydrate', a medicine of years past.

Terpin hydrate is derived by high-temperature acid treatment of "oil of turpentine", which is composed mostly of alpha- and beta-pinene. These compounds are termed "terpenes", but they are more often known in science as "isoprenoids"; they share a common biosynthetic pathway in plants and some insects. Traditional biochemistry obsesses over lipids, carbohydrates, proteins, and amino acids... this is a very animal-centric perspective, and I think that isoprenoids are only excluded because they don't have a connection with the publicly well-known Big Three in nutrition (fat, carb, protein). They are the major component in all essential oils and most natural resins.

A medicine called "Elixer Terpin Hydrate" was available from the beginning of this century right up until the early 90's, and was a popular expectorant used to treat bronchitis. My parents remember the stuff fondly, but the FDA pulled it off the market because there was no indication that the active ingredient actually did anything. The original version was loaded with codeine and contained more alcohol than vodka... so that could explain why it was so popular.

See "Patent Medicine" for a fascinating look at the not-so-distant past of the pharmaceutical industry.