Glycolipids of a halotolerant, moderately halophilic bacterium II. biosynthesis of glucuronosyldiglyceride by cell-free particles

1. 1. Particles isolated, after sonication, from cells grown on glucose as sole carbon source synthesized ¹⁴C-labelled glucuronosyldiglyceride from UDP-[¹⁴C]glucuronic acid and externally added diglycerides. 2. 2. The diglycerides were added directly onto lyophilized particles or were dispersed in Triton X-100. Only bacterial 1,2-diglycerides could serve as substrate for the enzyme. Diglycerides which contained at least 50% cyclopropane acids were the preferred substrate. 3. 3. The ¹⁴C-labelled glycolipid synthesized, was isolated by thin-layer chromatography, degraded by mild alkaline hydrolysis and the water soluble product was purified by paper electrophoresis. The purified product contained glycerol and glucuronic acid in a 1 : 1 ratio. 4. 4. The system required Mg²⁺ for activity. KC1 and NaCl were inhibitory at all concentrations tested.