The previous post about DEAE cellulose reminded me of a classic experiment in chromatography: the separation of dyes. This is where the name comes from - even though most of what we separate anymore isn’t colored, it stuck. Mikhail Tsvet, a Russian chemist, used it to separate chlorophylls and carotenes, two classes of brilliantly colored biomolecules. Lucky for you, when I have nothing to do on a Sunday afternoon, I do…well, the exact same thing I do during the week, only for free. In my kitchen. It gets messy. Today wasn’t so bad.

I went to the grocery and bought the regular food coloring everyone gets, the four little plastic bottles with red, blue, green, and yellow. If you look at the ingredients, my box says there is: water, propylene glycol, yellow 5, red 40, and blue 1. Propylene glycol, mentioned on the fomepizole entry, is just a nontoxic alcohol that probably makes the dyes a bit more soluble. Notice there are only three dyes. This is probably not so surprising since we have yellow, red, and blue, and the only one without its own dye is green. Presumably the venerable principle of “yellow and blue make green” is at work here. We set out to verify the YABMG theory.

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When cannibis was first being studied, the active principle was isolated and found to be delta-9-tetrahydrocannabinol, shown below. Later on, studies showed that there were, in fact, endogeneous receptors that interacted with the compound. In abundance. We termed it the cannabinoid receptor, for lack of a better word. Endogeneous or not, the only thing we knew that would fit in it came from a drug of abuse!
This was baffling: Nature tends to be pretty parsimonious. A truly vestigial receptor class was unlikely. So did we evolve in the (continuous) presence of dope fields? Surely not. This was a strong indication that there was some sort of endogeneous cannabinoid. The search was on. Despite having known about marijuana for literal millenia, we didn’t find an endogenous ligand until 1992! This came out of Raphael Mechoulam’s lab - the same guy who isolated THC back in 1964! To be fair, even though THC was long-since discovered, we only knew about cannabinoid receptors as recently as 1988.

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Many people who come here from Gilead seem to peek at the Tamiflu page and take off. Gilead, you see, are actually the people who came up with Tamiflu, not Roche. They simply purchased the rights. After the whole bird flu thing pushed it into the public eye, Gilead and Roche had a brief spat, which was settled a few months later.

In general, this is the sort of thing Gilead make: small molecule antivirals. Let’s take a look at another Gilead drug, adefovir:

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