title: A retaining endo-beta-mannosidase from a dicot plant, cabbage.
abstract: An endo-beta-mannosidase [EC 3.2.1.152, glycoside hydrolase family 2], which hydrolyzes the Manbeta1-4GlcNAc linkage of N-glycans in an endo-manner, has been found in plant tissues [Ishimizu, T., Sasaki, A., Okutani, S., Maeda, M., Yamagishi, M., and Hase, S. (2004) J. Biol. Chem. 279, 38555-38562]. So far, this glycosidase has been purified only from a monocot plant, a lily. Here, an endo-beta-mannosidase was purified from a dicot plant, cabbage (Brassica oleracea), and characterized. The cabbage endo-beta-mannosidase consists of four polypeptides. These four polypeptides are encoded by a single gene, whose nucleotide sequence is homologous to those of the lily and Arabidopsis endo-beta-mannosidase genes. 1H NMR analysis of the stereochemistry of the hydrolysis of pyridylaminated (PA) Manalpha1-6Manbeta1-4GlcNAcbeta1-4GlcNAc showed that the cabbage endo-beta-mannosidase is a retaining glycoside hydrolase, as are other glycoside hydrolase family 2 enzymes. The enzymatic characteristics, including substrate specificity, of the cabbage enzyme are very similar to those of the lily enzyme. These endo-beta-mannosidases specifically act on Man(n)Manalpha1-6Manbeta1-4GlcNAcbeta1-4GlcNAc-PA (n = 0 to 2). These results suggest that the endo-beta-mannosidase is present in at least the angiosperms, and has common roles, such as the degradation of N-glycans.
authors.affiliation: Department of Chemistry, Graduate School of Science, Osaka University, Osaka 560-0043.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Ishimizu
authors.forename: Chikako
authors.initials: C
authors.lastname: Hashimoto
authors.forename: Renzo
authors.initials: R
authors.lastname: Kajihara
authors.forename: Sumihiro
authors.initials: S
authors.lastname: Hase
mesh_terms: D000595:Amino Acid Sequence; D001937:Brassica / Q000201:enzymology* / Q000235:genetics; D002240:Carbohydrate Sequence; D004795:Enzyme Stability; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D008361:Mannosidases / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D008956:Models, Chemical; D008968:Molecular Conformation; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000737:chemistry / Q000378:metabolism; D018515:Plant Leaves / Q000201:enzymology / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity
chemical_list: D009844:Oligosaccharides; D008361:Mannosidases; C119276:endo-beta-mannosidase