A retaining endo-beta-mannosidase from a dicot plant, cabbage

作者：Ishimizu Takeshi; Hashimoto Chikako; Kajihara Renzo; Hase Sumihiro^*

来源：Journal of Biochemistry, 2006, 139(6): 1035-1043.

DOI：10.1093/jb/mvj116

• anomer proton
• endo-beta-mannosidase
• mannosidase
• N-glycan
• plant

An endo-beta-mannosidase [EC 3.2.1.152, glycoside hydrolase family 2], which hydrolyzes the Man beta 1-4GlcNAc 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. H-1 NMR analysis of the stereochemistry of the hydrolysis of pyridylaminated (PA) Mana1-6Man beta 1-4GlcNAc beta 1-4GlcNAc 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)Man alpha 1-6Man beta 1-4GlcNAc beta 1-4GlcNAc-PA (n = 0 to 2). These results suggest that the endo-p-mannosidase is present in at least the angiosperms, and has common roles, such as the degradation of N-glycans.

• 出版日期2006-6