[The presence of glycosyltransferases on chromatin acceptors in monkey liver nuclear membranes (author's transl)].
Nuclei were prepared from monkey hepatocytes by centrifugation of the homogenate on a cushion of 2.3 M sucrose, during 45 min at 100000 X g. The yield was 2.2 x 10(7) nuclei per g of liver, and 70% of te homogenate DNA was recovered in these nuclei. An electron microscopic study as well as a biochemical analysis of marker enzymes showed that the nuclei are not contaminated by other subcellular fractions, especially endoplasmic reticulum. A mannosyltransferase and an N-acetylglucosaminyltransferase, working on endogenous glycoproteic acceptors, are present in the nuclei for 1.4 and 6.5% of the homogenate activities, respectively. The nuclei are hydrolysed by DNAse I. The suspension, adjusted in 1.9 M sucrose, was centrifuged for 2 h at 100000 X g, under buffer layer. Purified nuclear membranes were collected at the interface. These membranes did not contain any more endoplasmic reticulum enzyme activities, but the mannosyl and N-acetylglucosaminyltransferase activities were still present. They essentially work on an exogenous chromatin acceptor, prepared by lysis of the nuclei. The eventual role of these glycosyltransferases in the glycosylation of non-histone proteins is discussed.
D000117:Acetylglucosamine / Q000378:metabolism; D000818:Animals; D002458:Cell Fractionation; D002843:Chromatin / Q000201:enzymology*; D004901:Erythrocebus patas; D005260:Female; D005964:Glucosyltransferases / Q000378:metabolism*; D006602:Hexosyltransferases / Q000378:metabolism*; D008099:Liver / Q000201:enzymology*; D008297:Male; D008364:Mannosyltransferases / Q000378:metabolism*; D008854:Microscopy, Electron; D017351:N-Acetylglucosaminyltransferases; D009685:Nuclear Envelope / Q000201:enzymology
D002843:Chromatin; D005964:Glucosyltransferases; D006602:Hexosyltransferases; D008364:Mannosyltransferases; D017351:N-Acetylglucosaminyltransferases; C037649:N-acetyllactosaminide beta-1,6-N-acetylglucosaminyltransferase; D000117:Acetylglucosamine
Présence de glycosyltransferases à accepteurs chromatiniens dans les membranes nucléaires d'hépatocytes de singe.