Mechanism of Action of Angustmycins, Nucleoside Antibiotics

Abstract

Angustmycins A and C, produced by Streptomyces hygroscopicus, are nucleoside antibiotics: angustmycin A is 6-amino-9-(L-1,2-fucopyranoseenyl)-purine and angustmycin C 6-amino-9-(β-D-psicofuranosyl)-purine.^1–4) They were observed to exhibit an inhibitory activity against experimental infections and transplantable tumors in animals⁶⁾.

The activity of angustmycins A and C was reversed by adenosine, guanosine, guanine and related substances. It indicated that both angustmycins may act as antimetabolites in purine biosynthesis. The inhibition index suggested that guanosine synthesis is more interfered than adenosine synthesis in the presence of angustmycins. ⁵⁾

This paper describes the results of further experiments concerning the mode of action of these nucleoside antibiotics, indicating that both angustmycins may inhibit the process of biosynthesis of guanosine monophosphate from xanthosine monophosphate.