Glycoside hydrolase family 18 (GH18) chitinases, which catalyze the biodegradation of β-1,4 glycosidic bond in amino polysaccharides via a substrate-assisted retention mechanism, are widely distributed in nature and have diverse functions. Many organisms produce several GH18 chitinases which take part in multiple physiological processes, including tissue degradation and remodeling, nutrition uptake, invasion and pathogenesis as well as immune response regulation. Because of their physiological importance, mounting crystallographic investigations have been conducted for GH18 chitinases, and their inhibitors have also been developed. However, there is still much unclear concerning these enzymes, such as the explicit mechanisms underlying their involvement in disease development, the direct connection of structure to processivity, and selectivity of the inhibitors. In this article, research progress on biological function, structural information and inhibition of GH18 chitinases has been reviewed and the remaining uncertainties are highlighted. This review may also facilitate those who intent to develop drugs or agrochemicals based on these enzymes.

糖苷水解酶家族18（GH18）几丁质酶通过底物辅助的保留机制催化氨基多糖中β-1,4糖苷键的生物降解，在自然界广泛分布并且具有多种功能。许多生物体会产生几种GH18几丁质酶，它们参与多种生理过程，包括组织降解和重塑，营养吸收，入侵和发病机理以及免疫应答调节。由于它们的生理重要性，已经对GH18几丁质酶进行了固定的晶体学研究，还开发了其抑制剂。但是，关于这些酶，仍然存在很多不清楚的地方，例如它们参与疾病发展的明确机制，结构与生产力的直接联系，和抑制剂的选择性。本文综述了GH18几丁质酶的生物学功能，结构信息和抑制作用的研究进展，并指出了尚存在的不确定性。这篇评论也可以为那些打算基于这些酶开发药物或农用化学品的人们提供便利。