Iseli B, Armand S, Boller T, Neuhaus J M, Henrissat B
Botanisches Institut, Universität Basel, Switzerland.
FEBS Lett. 1996 Mar 11;382(1-2):186-8. doi: 10.1016/0014-5793(96)00174-3.
Bacterial, fungal, animal, and some plant chitinases form family 18 of glycosyl hydrolases. Most plant chitinases form the family 19. While some chitinases also have lysozyme activity, animal lysozymes belong to different families. For glycosyl hydrolases, two reaction mechanisms are possible, leading to either retention or inversion of the anomeric configuration. We analyzed by HPLC the stereochemical outcome of the hydrolysis catalyzed by cucumber and bean chitinases, belonging to families 18 and 19, respectively. Cucumber chitinase used the retaining mechanism as known for bacterial chitinases and hen egg white lysozyme for which the mechanism has been determined. In contrast, bean chitinase catalyzed the hydrolysis of chitooligosaccharides with overall inversion of anomeric configuration.
细菌、真菌、动物以及一些植物的几丁质酶构成了糖基水解酶家族18。大多数植物几丁质酶构成家族19。虽然一些几丁质酶也具有溶菌酶活性，但动物溶菌酶属于不同家族。对于糖基水解酶来说，可能有两种反应机制，导致异头构型的保留或翻转。我们通过高效液相色谱法分析了分别属于家族18和19的黄瓜和菜豆几丁质酶催化水解的立体化学结果。黄瓜几丁质酶采用了已知的细菌几丁质酶和已确定机制的鸡蛋清溶菌酶所使用的保留机制。相比之下，菜豆几丁质酶催化了具有异头构型整体翻转的几丁寡糖的水解。
