Enzymatic Glucosylation of Dolichyl Monophosphate Formed Via Cytidine Triphosphate in Calf Brain Membranes

Publisher Website
Google Scholar
Abstract
When calf brain membrane preparations containing endogenous dolichyl [32P]monophosphate (Dol-32P), prelabeled enzymatically by [.gamma.-32P]-CTP, were incubated with unlabeled UDP-glucose, a mild acid-labile [32P]phosphoglucolipid was formed. The biosynthesis of the [32P]phosphoglucolipid is dependent on the concentration of UDP-glucose added, and no [32P]phosphoglycolipid appeared when UDP-glucose was replaced by ADP-glucose, UDP-xylose, UDP-galactose, UDP-mannose or UDP-glucuronic acid. The 32P-labeled product formed by the UDP-glucose-dependent reaction is chemically and chromatographically identical to glucosylphosphoryldolichol. Several enzymatic parameters of the glucosylation of the specific pool of Dol-P, synthesized by the CTP-mediated kinase, and the total available pool of Dol-P were compared by a double-label assay; endogenous, prelabeled Dol-32P and UDP-[3H]glucose were used as substrates.