title: The carbohydrate moiety of alpha-galactosidase from Trichoderma reesei.
abstract: Alpha-galactosidase from Trichoderma reesei is a glycoprotein that contains O- and N-linked carbohydrate chains. There are 6 O-linked glycans per protein molecule that are linked to serine and threonine and can be released by beta-elimination. Among these are monomers: D-glucose, D-mannose, and D-galactose; dimers: alpha1-6 D-mannopyranosyl-alpha-D-glycopyranoside and alpha1-6 D-glucopyranosyl-alpha-D-galactopyranoside and one trimer: alpha-D-glucopyranosyl-alpha1-2 D-mannopyranosyl-alpha1-6 D-galactopyranoside. N-linked glycans are of the mannose-rich type and may be released by treating the protein with Endo-beta-N-acetyl glycosaminidase F or by hydrozinolysis. The enzyme was deglycosylated with Endo-beta-N-acetyl glycosaminidase F as well as with a number of exoglycosidases that partially remove the terminal residues of O-linked glycans. The effect of enzymatic deglycosylation on the properties of alpha-galactosidase has been considered. The effects of tunicamycin and 2-deoxyglucose on the secretion and glycosylation of the enzyme during culture growth have been analysed. The presence of two glycoforms of alpha-galactosidase differing in the number of N-linked carbohydrate chains and the microheterogeneity of the carbohydrate moiety of the enzyme are described.
authors.affiliation: St Petersburg Technical University, Biophysics Department, Russia.
authors.forename: A N
authors.initials: AN
authors.lastname: Savel'ev
authors.forename: E V
authors.initials: EV
authors.lastname: Eneyskaya
authors.forename: L S
authors.initials: LS
authors.lastname: Isaeva-Ivanova
authors.forename: K A
authors.initials: KA
authors.lastname: Shabalin
authors.forename: A M
authors.initials: AM
authors.lastname: Golubev
authors.forename: K N
authors.initials: KN
authors.lastname: Neustroev
mesh_terms: D000595:Amino Acid Sequence; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D002241:Carbohydrates / Q000737:chemistry; D003847:Deoxyglucose / Q000494:pharmacology; D004795:Enzyme Stability; D005656:Fungal Proteins / Q000737:chemistry; D006023:Glycoproteins / Q000737:chemistry; D006031:Glycosylation; D007700:Kinetics; D008969:Molecular Sequence Data; D011134:Polysaccharides / Q000737:chemistry; D014242:Trichoderma / Q000201:enzymology* / Q000235:genetics; D014415:Tunicamycin / Q000494:pharmacology; D000519:alpha-Galactosidase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism
chemical_list: D002241:Carbohydrates; D005656:Fungal Proteins; D006023:Glycoproteins; D011134:Polysaccharides; D014415:Tunicamycin; D003847:Deoxyglucose; D000519:alpha-Galactosidase