Action of Pepsin on Synthetic Substrates

Abstract

IN a previous communication¹ regarding the action of pepsin on two of its synthetic substrates, acetyl-L-phenylalanyl-L-tyrosine and N-acetyl-L-tyro-syl-L-tyrosine, results were obtained which seemed to indicate that the products of the hydrolysis were released from the enzyme-substrate complex at different rates, and that it was this phenomenon which accounted for the logarithmic course of the reaction. A communication afterwards received from Dr. N. M. Green showed that the release of the second product at a very slow rate, according to the hypothesis presented, would not lead to a logarithmic course (see accompanying communication by Dr. N. M. Green). A further study of the hydrolysis of acetyl-L-phenylalanyl-L-tyrosine by pepsin was therefore made, and has shown the conclusions that were previously drawn to be incorrect.