On the loss of uricolytic activity during primate evolution--I. Silencing of urate oxidase in a hominoid ancestor.

Urate oxidase activity is not detectable in liver homogenates from the gibbon, orangutan, chimpanzee, gorilla and human. Liver homogenates from five genera of Old World and two genera of New World monkeys have easily detectable levels of urate oxidase activity. There is no evidence for extant detectable intermediate steps in the loss of urate oxidase activity in the hominoids. Urate oxidase activity from Old World and New World monkeys is stable, a simple observation which debunks a long-standing myth. Urate oxidase activity was silenced in an ancestor to the five living genera of hominoids after divergence from the Old World monkeys.