Action of galactose oxidase on galactolipids.
Exposure of galactose-containing glycosphingolipids and certain glycoproteins to galactose oxidase followed by treatment with sodium borotritide has been used to label specifically the terminal galactose and N-acetylgalactosamine moieties of these glycoconjugates. This labelling procedure was shown to be ineffective with a lipid isolated from rat testis, 1-O-palmityl-2-O-palmitoyl-3 beta-galactosyl-glycerol, under conditions which resulted in excellent labelling of galactosyl-ceramide. Monogalactosyldiacylglycerol was also poorly labelled by this procedure. It was shown that neither 1-O-palmityl-2-O-palmitoyl-3 beta-(3'-sulfogalactosyl)-glycerol nor sulfogalactosyl-ceramide ("classical sulfatide") was labelled by this procedure indicating that sulfate substitution of the galactose inhibits the action of galactose oxidase. The labelling of galactosyl-ceramide was not inhibited in the presence of the galactoglycerolipid, sulfogalactoglycerolipid, or sulfatide. The property of the lipid aglycone responsible for inhibiting galactose oxidase action remains to be determined.
D000818:Animals; D005690:Galactose; D005691:Galactose Dehydrogenases / Q000378:metabolism; D005692:Galactose Oxidase / Q000378:metabolism*; D006017:Glycolipids; D006023:Glycoproteins; D006028:Glycosphingolipids; D007700:Kinetics; D008297:Male; D051381:Rats; D013379:Substrate Specificity; D013737:Testis
D006017:Glycolipids; D006023:Glycoproteins; D006028:Glycosphingolipids; D005691:Galactose Dehydrogenases; D005692:Galactose Oxidase; D005690:Galactose