The characteristics of hexokinase from Locusta migratoria muscle

Abstract

Hexokinase activity was demonstrated in extracts of thorax muscle and salivary gland of L. migratoria. The characteristics of the enzyme are similar to those of the hexokinase present in brain extracts. In the presence of adenosine triphosphate and Mg++ ions, D-glucose, D-mannose, D-fructose and D-glucosamine are utilized. Utilization of all substrates is inhibited by glucose-6-phosphate or fructose-6-phosphate, and that of fructose by glucose, mannose and N-acetylglucosamine. An ester stable to acid hydrolysis, probably a mixture of glucose-6-phosphate and fructose-6-phosphate, was identified as a product of phosphorylation of fructose. Extracts of muscle and of salivary gland contain an amylase which hydrolyzes glycogen present in extracts of fed insects.