Reaction: Xm-(1→4)-β-D-GlcpN-(1→4)-β-D-GlcpNAc-(1→4)-Xn + H2O = Xm-(1→4)-β-D-GlcpN-(1→4)-α-D-GlcpNAc + Xn
Glossary: X = [→4)-β-D-GlcpN/GlcNAc-(1→]; m > 1; n ≥ 0
Other name(s): chitosan hydrolase (ambiguous)
Systematic name: partially acetylated chitosan endo glucsamino-N-acetylglucosaminohydrolase (configuration-inverting)
Comments: The enzyme is an endo hydrolase that cleaves after the GlcN-GlcNAc diad in partially acetylated chitosan with subsite -2 specific for GlcN and subsite -1 specific for GlcNAc. The enzyme does not cleave fully deacetylated chitosans which are cleaved by chitosanases (EC 3.2.1.132) and glucosaminidases (EC 3.2.1.165) or fully acetylated chitins which are cleaved by chitinases (EC 3.2.1.14, EC 3.2.1.200, EC 3.2.1.201, EC 3.2.1.202) and N-acetylglucosaminidases (EC 3.2.1.52). The protein was found in the medium in which the plant pathogenic fungus Alternaria alternata was grown.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number:
References:
1. Kohlhoff, M., Niehues, A., Wattjes, J., Beneteau, J., Cord-Landwehr, S., El Gueddari, N.E., Bernard, F., Rivera-Rodriguez, G.R. and Moerschbacher, B.M. Chitinosanase: A fungal chitosan hydrolyzing enzyme with a new and unusually specific cleavage pattern. Carbohydr. Polym. 174 (2017) 1121-1128. [PMID: 28821036]