Suzuki Kazushi, Sugawara Noriko, Suzuki Megumi, Uchiyama Taku, Katouno Fuminori, Nikaidou Naoki, Watanabe Takeshi
Department of Applied Biological Chemistry, Faculty of Agriculture, Niigata University, Japan.
Biosci Biotechnol Biochem. 2002 May;66(5):1075-83. doi: 10.1271/bbb.66.1075.
To discover the individual roles of the chitinases from Serratia marcescens 2170, chitinases A, B, and C1 (ChiA, ChiB, and ChiC1) were produced by Escherichia coli and their enzymatic properties as well as synergistic effect on chitin degradation were studied. All three chitinases showed a broad pH optimum and maintained significant chitinolytic activity between pH 4 and 10. ChiA was the most active enzyme toward insoluble chitins, but ChiC1 was the most active toward soluble chitin derivatives among the three chitinases. Although all three chitinases released (GlcNAc)2 almost exclusively from colloidal chitin, ChiB and ChiC1 split (GlcNAc)6 to (GlcNAc)3, while ChiA exclusively generated (GlcNAc)2 and (GlcNAc)4. Clear synergism on the hydrolysis of powdered chitin was observed in the combination between ChiA and either ChiB or ChiC, and the sites attacked by ChiA on the substrate are suggested to be different from those by either ChiB or ChiC1.
为了探究粘质沙雷氏菌2170几丁质酶的各自作用，大肠杆菌表达了几丁质酶A、B和C1（ChiA、ChiB和ChiC1），并研究了它们的酶学性质以及对几丁质降解的协同作用。所有这三种几丁质酶均表现出较宽的最适pH值，且在pH 4至10之间保持显著的几丁质分解活性。在这三种几丁质酶中，ChiA对不溶性几丁质的活性最高，但ChiC1对可溶性几丁质衍生物的活性最高。尽管所有这三种几丁质酶几乎都仅从胶体几丁质中释放出(GlcNAc)2，但ChiB和ChiC1将(GlcNAc)6分解为(GlcNAc)3，而ChiA仅产生(GlcNAc)2和(GlcNAc)4。在ChiA与ChiB或ChiC的组合中，观察到对粉末状几丁质水解有明显的协同作用，并且推测ChiA在底物上的作用位点与ChiB或ChiC1的不同。
