Properties and Transglycosylation Reaction of a Chitinase from Nocardia orientalis |
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| Authors: | Fumio Nanjo Kazuo Sakai Masato Ishkawa Kiyoshi Isobe Taichi Usui |
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| Affiliation: | 1. NFI Laboratories, Yaizu Suisan Kagaku Industry Co., Ltd., Kogawashin-machi, Yaizu, Shizuoka, 425, Japan;2. Department of Agricultural Chemistry, Faculty of Agriculture, Shizuoka University, Ohya 836, Shizuoka, 422, Japan |
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| Abstract: | The hydrolytic products of a chitinase purified from Nocardia orientalis were examined on reduced (GIcNAc)n(n = 2~6). The rate of hydrolysis on reduced (GlcNAc)4^6 increased with increasing chain-length of A-acetylglucosamine residues, but the enzyme did not act on reduced (G1cNAc)2 or reduced (GlcNAc)3. Based on the analysis of the frequency distribution of bond cleavage on PNP-(GIcNAc)?(n = 2 ~ 5) in the initial hydrolysis, the enzyme was shown to release predominantly (G1cNAc)2 from the nonreducing end of each substrate. The enzyme, which is essentially a hydrolase, also catalyzed a transglycosylation reaction in an excess of (GlcNAc)4 as an initial substrate. In this case, the addition of ammonium sulfate to the reaction system resulted in a significant increase in (G1cNAc)6 production. The yield of the hexasaccharide was about 34% of the chitinase-catalyzed net decrease of (GlcNAc)4. The rate of the transglycosylation in the presence of ammonium sulfate greatly depended on the salt concentration, the temperature, and the substrate concentration. |
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