title: Studies on UDP-N-acetylglucosamine : alpha-mannoside beta-N-acetylglucosaminyltransferase of rat liver and hepatomas.
abstract: When homogenates of rat liver and hepatomas were centrifuged at 78 000 X g, over 90% of liver N-acetylglucosaminyltransferase assayed with beta-galactosidase- and beta-N-acetylhexosaminidase-treated asialofetuin as acceptor was recovered in the particulate fraction, while as much as 24% of hepatoma transferase was in the supernatant fraction. The particulate transferase solubilized by 0.2% sodium deoxycholate emerged from a DEAE-cellulose column at 0.04 M NaCl (transferase A). The supernatant fractions from all the hepatomas tested contained a second N-acetylglucosaminyltransferase eluted from the column at 0.02 M NaCl (transferase B). Transferase B was absent from liver supernatant fraction. The activities of these transferases toward various acceptors and the effect of beta-N-acetylhexosaminidase on their products suggest that both transferases are UDP-N-acetylglucosamine : alpha-mannoside beta-N-acetylglucosaminyltransferase. Although ovalbumin and glycopeptide V, which was isolated from pronase digest of ovalbumin, were good acceptors, transferase A utilized ovalbumin and glycopeptide V with apparent Km values of 0.44 and 0.33 mM, respectively, whereas the corresponding values for transferase B were 4.5 and 0.050 mM.
mesh_terms: D000818:Animals; D001212:Asialoglycoproteins; D060748:Fetuins; D005964:Glucosyltransferases / Q000378:metabolism*; D007700:Kinetics; D008099:Liver / Q000201:enzymology*; D008114:Liver Neoplasms, Experimental / Q000201:enzymology*; D008297:Male; D017351:N-Acetylglucosaminyltransferases / Q000378:metabolism*; D010047:Ovalbumin; D051381:Rats; D013347:Subcellular Fractions / Q000201:enzymology; D013379:Substrate Specificity; D000509:alpha-Fetoproteins
chemical_list: D001212:Asialoglycoproteins; D060748:Fetuins; D000509:alpha-Fetoproteins; C017029:asialofetuin; D010047:Ovalbumin; D005964:Glucosyltransferases; D017351:N-Acetylglucosaminyltransferases; C024850:alpha-1,3-mannosyl-glycoprotein beta-1,2-N-acetylglucosaminyltransferase I