Guanine is one of the five aromatic bases that make up the genetic code. They are listed below:

Why would one be more interesting than the others? Well, guanine ends up being the weird one in a bunch of ways…

First of all, it’s not very soluble. Yesterday’s molecule, cyclodextrin, showed some examples of how solubility could modulate things like how poisonous a substance is. Neither of the purines are terribly soluble (the purines are the larger bases; guanine and adenine). One of their metabolites is uric acid. This has terrible solubility as well, and it deposits in the joints in gout. Some animals that have to conserve water will excrete solid urate - birds, for example, and bats. Bat feces — or guano — are rich in both urate and guanine. It is from guano that we get the word guanine.

Read the rest of this entry »