title: Does an animal peptide: N-glycanase have the dual role as an enzyme and a carbohydrate-binding protein?
abstract: Recently, we have reported purification and characterization of a de-N-glycosylating enzyme, peptide: N-glycanase (PNGase) found in C3H mouse fibroblast L-929 cells, and designated L-929 PNGase [Suzuki T, Seko A, Kitajima K, Inoue Y, Inoue S (1994) J Biol Chem 269, 17611-18]. The unique properties of L-929 PNGase are that the enzyme had a high affinity to the substrate glycopeptide (e.g. Km = 114 microM for fetuin derived glycopentapeptide) and that the PNGase-catalysed reaction is strongly inhibited by the released free oligosaccharides but not by the free peptides formed, suggesting that L-929 PNGase is able to bind to a certain type of carbohydrate chain. In this study, we report the new findings of the mannan-binding property of L-929 PNGase: the de-N-glycosylating enzyme activity of L-929 PNGase was inhibited by yeast mannan and triomannose, Man alpha 1-->3(Man alpha 1-->6)Man, but not by mannose and alpha-methyl-D-mannoside. Furthermore, L-929 PNGase was revealed to bind to the glycan moiety of yeast mannan by using mannan-conjugated Sepharose 4B gel as a ligand, suggesting that L-929 PNGase could serve not only as an enzyme but also as a carbohydrate recognition protein in vivo. Such 'dual' properties found for animal-derived L-929 PNGase are unique and are not shared with other previously characterized plant- and bacterial-origin PNGases--PNGase A and PNGase F, respectively.
authors.affiliation: Department of Biophysics and Biochemistry, Graduate School of Science, University of Tokyo, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Suzuki
authors.forename: K
authors.initials: K
authors.lastname: Kitajima
authors.forename: S
authors.initials: S
authors.lastname: Inoue
authors.forename: Y
authors.initials: Y
authors.lastname: Inoue
mesh_terms: D000581:Amidohydrolases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D001212:Asialoglycoproteins / Q000737:chemistry; D001665:Binding Sites; D050260:Carbohydrate Metabolism; D002240:Carbohydrate Sequence; D002460:Cell Line; D060748:Fetuins; D007700:Kinetics; D008351:Mannans / Q000494:pharmacology; D008358:Mannose / Q000494:pharmacology; D051379:Mice; D008809:Mice, Inbred C3H; D008969:Molecular Sequence Data; D043524:Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase; D010455:Peptides / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000737:chemistry; D013402:Sugar Alcohols / Q000737:chemistry; D000509:alpha-Fetoproteins / Q000737:chemistry
chemical_list: D001212:Asialoglycoproteins; D060748:Fetuins; D008351:Mannans; D010455:Peptides; D013402:Sugar Alcohols; D000509:alpha-Fetoproteins; C017029:asialofetuin; D000581:Amidohydrolases; D043524:Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase; D008358:Mannose