MAN1B1, Endoplasmic reticulum mannosyl-oligosaccharide 1, 2-alpha-mannosidase, ER alpha-1,2-mannosidase, ER mannosidase 1, ERMan1, Man9GlcNAc2-specific-processing alpha-mannosidase, Mannosidase alpha class 1B member 1
This gene encodes an enzyme belonging to the glycosyl hydrolase 47 family. This enzyme functions in N-glycan biosynthesis, and is a class I alpha-1,2-mannosidase that specifically converts Man9GlcNAc to Man8GlcNAc isomer B. It is required for N-glycan trimming to Man5-6GlcNAc2 in the endoplasmic-reticulum-associated degradation pathway. Mutations in this gene cause autosomal-recessive intellectual disability. Alternative splicing results in multiple transcript variants. A related pseudogene has been identified on chromosome 11. [provided by RefSeq, Dec 2011],catalytic activity:Hydrolysis of the terminal (1->2)-linked alpha-D-mannose residues in the oligo-mannose oligosaccharide Man(9)(GlcNAc)(2).,cofactor:Calcium.,enzyme regulation:Inhibited by both 1-deoxymannojirimycin and kifunensine.,function:Involved in the maturation of Asn-linked oligosaccharides. Trim a single alpha-1,2-linked mannose residue from Man(9)GlcNAc(2) to produce Man(8)GlcNAc(2). The only product is the Man(8)GlcNAc(2) isomer B, the form lacking the middle-arm terminal alpha 1,2-mannose. It may be involved in glycoprotein quality control since it is important to target misfolded glycoproteins for degradation.,pathway:Protein modification, protein glycosylation.,similarity:Belongs to the glycosyl hydrolase 47 family.,tissue specificity:Widely expressed.,
