Studies on Chitin V. The Action of Mineral Acids on Chitin

Abstract

Chitin [from the marine crayfish, Jasus verreauxi] undergoes rapid and extensive degradation at 20[degree]C when dissolved in 10N hydrochloric acid, 21N sulphuric acid, or 85% phosphoric acid. Most of the degradation occurs in the first few minutes after the chitin is dissolved and the products formed are oligosaccharides (which are to some extent deacetylated) and N-acetyl-D-glucosamine. Glucosamine was not found except possibly in the smallest traces. "Colloidal" chitin, prepared by precipitation of chitin from solution in cold 21N sulphuric acid, has a very much shorter chain length than the chitin from which it was prepared. Chitin is more stable in dilute (2N) hydrochloric acid. At 25[degree]C only a negligible amount of hydrolysis occurs in 24 hr but at 100[degree]C significant amounts of glucosamine and oligosaccharides are formed. For complete hydrolysis of chitin with 5.7N hydrochloric acid it is necessary to heat at 100[degree]C for several hours. The preparation of chitin as a substrate for the enzyme chitinase is discussed in the light of these findings.