Glucosamine-6-phosphate synthesis in the crayfish epidermis

Abstract

1. 1. Activity of an enzyme which synthesizes glucosamine-6-phosphate, a precursor of chitin, was found in crayfish epidermis. 2. 2. In crude enzyme preparations no need for an amino source could be demonstrated. 3. 3. Both fructose-6-phosphate and glucose-6-phosphate could serve as substrates, but not mannose-6-phosphate or galactose-6-phosphate. 4. 4. No activity of this enzyme was detected during intermolt and early premolt. Activity began to rise in late premolt and reached its peak in postmolt. 5. 5. Acetylglucosamine level in epidermis and midgut gland was found to be higher in late premolt stage D 3 than in early premolt stage D 0 or postmolt stage B. 6. 6. Glucosamine level was lowest in stage B.