Purification and characterization of a neutral processing mannosidase from calf liver acting on (Man) sub(9)(GlcNAc) sub(2) oligosaccharides

• Published in: European journal of biochemistry Vol. 157; no. 3; pp. 563 - 570
• Main Authors: Schweden, J, Legler, G, Bause, E
• Format: Journal Article
• Language: English
• Published: 01.01.1986
• Subjects: cattle; mannosidase; microsomes
• ISSN: 0014-2956

A processing mannosidase acting on (Man) sub(9)(GlcNAc) sub(2) oligosaccharides, Man sub(9) mannosidase, has been purified 2190-fold from calf liver crude microsomes by a four-step procedure involving (a) differential salt/detergent extraction, (b) affinity chromatography on AH-Sepharose 4B with N-5-carboxypentyl-1-deoxy-mannojirimycin as ligand, (c) ConA-Sepharose and (d) DEAE-Sephacel chromatography. (Man) sub(9) mannosidase has a subunit molecular mass of 56 kDa and does not bind to ConA-Sepharose, indicating the absence of high-mannose oligosaccharides. The enzyme has a pH optimum close to pH 6.0 and requires divalent cations for activity, Ca super(2+) being most effective. It is inhibited by 1-deoxymannojirimycin (dMM), N-methyl-dMM and N-5-carboxypentyl-dMM with K sub(i) = 7 mu M, 75 mu M, and 140 mu M, respectively.