A protein-glucan intermediate during paramylon synthesis.
A sodium deoxycholate extract containing glucosyltransferase activity was obtained from a particulate preparation from Euglena gracilis. It transferred glucose from UDP-[14C]glucose into material that was precipitated by trichloroacetic acid. This material released beta-(1 leads to 3)-glucan oligosaccharides into solution on incubation with weak acid, weak alkali and beta-(1 leads to 3)-glucosidase. The products of the incubation of the deoxycholate extract with UDP-[14C]glucose were analysed by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. Radioactive bands were obtained that had the properties of beta-(1 leads to 3)-glucan covalently linked to protein by a bond labile to weak acid. High-molecular-weight material containing a beta-(1 leads to 3)-glucan was also shown to be present by gel filtration. The bond linking glucan to aglycone is possibly a pyrophosphate linkage. It is proposed that in Euglena gracilis beta-(1 leads to 3)-glucan (paramylon) is synthesized on a protein primer.
D000818:Animals; D002850:Chromatography, Gel; D004591:Electrophoresis, Polyacrylamide Gel; D005056:Euglena gracilis / Q000201:enzymology; D005936:Glucans / Q000096:biosynthesis*; D005964:Glucosyltransferases / Q000378:metabolism; D011485:Protein Binding; D011509:Proteoglycans / Q000096:biosynthesis*; D014238:Trichloroacetic Acid; D014532:Uridine Diphosphate Glucose / Q000378:metabolism
D005936:Glucans; D011509:Proteoglycans; C003045:paramylon; D014238:Trichloroacetic Acid; D005964:Glucosyltransferases; D014532:Uridine Diphosphate Glucose