THE FORMATION OF ACETATE IN BRAIN TISSUE SUSPENSIONS

Observations have been made on methods for the determination of acetate and acyl phosphate in tissue suspensions. Previous work on the formation of acetate by respiring brain suspensions, especially in the presence of added pyruvate, has been confirmed. No evidence could be obtained that the substance formed is actually acetyl phosphate, which breaks down to yield acetic acid in the course of the estimation or enzymatically during the incubation of the tissue. The amount of acetate formed in brain suspensions is increased by the presence of malonate. It seems also to be increased by the addition of malate or α-ketoglutarate and by thiamine. Spontaneous breakdown of pyruvate could account for part of the acetate formed from pyruvate added to tissue. Fluoroacetic acid interferes with the determination of acetic acid. There was no evidence that it increases the formation of acetate by rat brain tissue suspensions. It does not affect the oxygen uptake of these suspensions with glucose or pyruvate as substrates.