BIOGENESIS OF D-4-AMINO-3-ISOXAZOLIDONE AND O-CARBAMYL-D-SERINE

Abstract

It was observed that Streptomyces sp. No. 3558 produced D-4-amino-3-isoxazolidone and 0-carbamyl-D-serine simultaneously. The production of 0-carbamyl-D-serine occurred earlier than that of D-4-amino-3-isoxazolidone in the fermentation process.
0-Carbamyl-D-serine was not converted into D-4-amino-3-isoxazolidone by the cells of the Streptomyces. The use of ¹⁴C-labelled 0-carbamyl-D-serine also showed that it was not significantly incorporated into the isoxazolidone molecule by the growing cells.
Either DL-serine-3-¹⁴C or glycine-¹⁴C (U) was significantly incorporated into 0-carbamyl-D-serine and D-4-amino-3-isoxazolidone in the biosynthetic process. D-Glucose-¹⁴C (U) was also biosynthetically converted into 0-carbamyl-D-serine.
A plausible pathway in the biosynthesis of these two antibiotics is presented.