Acetylation.

Abstract

Acetylation is a process sometimes used by the body as a method of detoxication. When, for example, p-amino-benzoic acid is fed either to man or to rabbit, it is partly excreted as p-acetyl-aminobenzoic acid. It has seemed to us that this reaction might find an application in studies dealing with intermediary metabolism. That acetaldehyde and acetic acid are two products formed in the degradation of foodstuffs is generally believed. The evidence for their formation, like the evidence for the formation of other substances which are supposed to represent the intermediary steps in the metabolism of foodstuffs, is, as a rule, indirect rather than direct. By using such a substance as p-amino-benzoic acid, we are enabled to fix, as it were, the acetyl group. Since the acetylated compound formed can be recovered in the urine, and its amount determined, a measure of the extent to which acetylation occurs in the body may be obtained.

An important question now arises, to what extent will acetylation be affected if, in addition to the p-amino-benzoic acid, we feed the rabbit various substances which we have reason to believe influence the amount of acetaldehyde or acetic acid formed in the body? The results might give us more direct, more concrete evidence as to whether substances do or do not pass through the acetic aldehyde-acetic acid stage in the course of their degradation in the body.

Using rabbits as our test animals, we first fed them p-amino-benzoic acid for 4 days, then, in addition, the substance under examination for 4 days, and, finally, the p-amino-benzoic acid alone for 4 more days. The 24 hour samples of urine were collected, and the acetylated compound recovered and weighed.