title: Glycosylation of yeast aspartyl-tRNA synthetase. Affinity labelling by glucose and glucose 6-phosphate.
abstract: Several lines of evidence establish that the crystallizable aspartyl-tRNA synthetase from Baker's yeast contains some covalently bound glucose: (i) a positive staining of the enzyme was obtained after polyacrylamide gel electrophoresis followed by the concanavalin A-peroxidase test which is specific for glucose and mannose containing proteins; (ii) thin-layer chromatography and gas-liquid chromatography revealed the presence of glucose in enzyme hydrolysates; (iii) immunoaffinoelectrophoresis in agarose gels containing concanavalin A and antibodies raised against aspartyl-tRNA synthetase showed that the enzyme was able to precipitate entirely in the lectin. Finally incubation of the enzyme with [14C]glucose or [14C]glucose 6-phosphate led to the incorporation of radioactivity into trichloroacetic acid-precipitable protein. Indeed immunoprecipitation of [14C]glucose-labelled aspartyl-tRNA synthetase with specific antibodies using the rocket method followed by autoradiography gave a radioactive peak. This last result also demonstrates the possibility of in vitro glycosylation of yeast aspartyl-tRNA synthetase.
mesh_terms: D000345:Affinity Labels; D000604:Amino Acyl-tRNA Synthetases / Q000378:metabolism*; D001226:Aspartate-tRNA Ligase / Q000378:metabolism*; D055598:Chemical Phenomena; D002621:Chemistry; D004586:Electrophoresis / Q000379:methods; D005947:Glucose / Q000378:metabolism; D019298:Glucose-6-Phosphate; D005958:Glucosephosphates / Q000378:metabolism; D007122:Immunoelectrophoresis; D011485:Protein Binding; D012441:Saccharomyces cerevisiae / Q000201:enzymology*
chemical_list: D000345:Affinity Labels; D005958:Glucosephosphates; D019298:Glucose-6-Phosphate; D000604:Amino Acyl-tRNA Synthetases; D001226:Aspartate-tRNA Ligase; D005947:Glucose