Accepted name: mannosylglycoprotein endo-β-mannosidase
Reaction: Hydrolysis of the α-D-mannosyl-(1→6)-β-D-mannosyl-(1→4)-N-acetyl-β-D-glucosaminyl-(1→4)-N-acetyl-β-D-glucosaminyl sequence of glycoprotein to α-D-mannosyl-(1→6)-D-mannose and N-acetyl-β-D-glucosaminyl-(1→4)-N-acetyl-β-D-glucosaminyl sequences
Other name(s): endo-β-mannosidase
Comments: The substrate group is a substituent on N-4 of an asparagine residue in the glycoprotein. The mannose residue at the non-reducing end of the sequence may carry further α-D-mannosyl groups on O-3 or O-6, but such a substituent on O-3 of the β-D-mannosyl group prevents the action of the enzyme. The enzyme was obtained from the lily, Lilium longiflorum.
1.  Ishimizu, T., Sasaki, A., Okutani, S., Maeda, M., Yamagishi, M. and Hase, S. Endo-β-mannosidase, a plant enzyme acting on N-glycan. Purification, molecular cloning, and characterization. J. Biol. Chem. 279 (2004) 38555–38562. [PMID: 15247239]
2.  Sasaki, A., Yamagishi, M., Mega, T., Norioka, S., Natsuka, S. and Hase, S. Partial purification and characterization of a novel endo-β-mannosidase acting on N-linked sugar chains from Lilium longiflorum thumb. J. Biochem. (Tokyo) 125 (1999) 363–367. [PMID: 9990135]
[EC created 2005]