Variation in rates of activity and inhibition of serum cholinesterase among anthropoid primates

Cholinesterase activity in the plasma of five hominoid and five cercopithecoid species was measured and characterized by profiles of inhibition by dibucaine and sodium fluoride. Chimpanzees and gorillas strongly resemble humans, and differ from other hominoids and cercopithecoids, in patterns of dibucaine and fluoride resistance and relative activity toward various thio esters. “Silent” cholinesterase phenotypes of probable veterinary significance, and analogous to a rare human variant, are apparently normal in some catarrhine species and are present as a polymorphism among orangutans and lion-tailed macaques.