Studies on Chitin I. Enzymic Degradation of Chitin and Chitin Esters

Abstract

A study was made of the enzymic degradation of chitin and the Na salt of chitin sulfuric acid by a chitinase prepared from the intestinal tract of the snail. Helix aspersa. It is shown that, in a citrate-phosphate buffer, the pH for optimum activity is 4.8 for both substrates. Chitin, prepared from both lobster cuticle and fly puparia, is broken down by snail chitinase to N-acetyl-D-glucosamine, although there is also a trace of D-glucosamine. The Na salt of chitin sulfuric acid also breaks down to N-acetyl-D-glucosamine and D-glucosamine. In both cases N-acetyl-D-glucosamine was isolated. The chitinase is without action on chitin nitrate. Acid hydrolysis of both chitin nitrate and the Na salt of chitin sulfuric acid leads to the formation of D-glucosamine, which was isolated as 2-hydroxynaphthylidene glucosamine. All attempts to phosphorylate chitin were unsuccessful. The structure of chitin is discussed.