Enzymatic synthesis of glucosamine 6-phosphate in rat liver.

Leloir and Cardini in 1953 described an enzyme from Neurospora crassa which formed glucosamine from n-hexose 6-phosphate and n-glutamine (2). Formation of glucosamine by cell-free extracts of streptococci in the presence of glucose, adenosine triphosphate, and glutamine was also reported by Lowther and Rogers (3). Although no similar system was described in mammalian tissues, evidence obtained in vivo from several laboratories has clearly established that the carbon chain of glucose is incorporated intact into the glucosamine portion of the mucopolysaccharides of mammals and microorganisms (4-7). In the present communication, an enzyme system from rat liver homogenates is described which forms Gm6P’ by the following reaction: n-Glucose 6-phosphate + n-glutamine + n-glucosamine g-phosphate + n-glutamate Results