The role of glutamine in the biosynthesis of hyaluronate by streptococcal suspensions

Abstract

Washed suspensions of streptococcus T13 synthesize hyaluronate from glucose and L-glutamine in the presence of phosphate and Mg. L-Glutamine can be replaced by an equivalent molar concentration of ammonium L-glutamate, or by L-serine, L-arginine and L-asparagine, provided L-glutamate also is added. When freshly prepared, the cell suspensions synthesize hyaluronate from glucose and ammonium ions alone, or from amino acids, giving rise to ammonia. In the presence of ammonium L-glutamate, synthesis is much more sensitive to methionine sulphoxide than when L-glutamine is added. Cell-free extracts of streptococci will synthesize glucosamine from glutamine but not from ammonium glutamate. Highly efficient conversion of labelled ammonium ions into hyaluronate glucosamine is effected by streptococci in the presence of unlabelled L-glutamate. Glutamine is proposed as an essential intermediate in the synthesis of hyaluronate glucosamine by S. haemolyticus, strain T13.