Nawani N N, Kapadnis B P, Das A D, Rao A S, Mahajan S K
Department of Microbiology, University of Pune, Pune and Molecular Biology and Agriculture Division, Bhabha Atomic Research Centre, Mumbai, India.
J Appl Microbiol. 2002;93(6):965-75. doi: 10.1046/j.1365-2672.2002.01766.x.
Purification and characterization of a chitinase from Microbispora sp. V2.
The chitinase from Microbispora sp. V2 was purified to homogeneity by gel filtration chromatography with 4.6% recovery. It had a molecular weight of 35 kDa and showed maximum activity towards p-nitrophenyl-beta-d-N,N'-diacetylchitobiose, indicating a chitobiosidase activity. The enzyme had a pH optimum of 3.0 and temperature optimum of 60 degrees C. It was stable in a wide pH range from 3.0 to 11.0, retaining 61% activity at pH 3.0 and 52% activity at pH 11.0. It retained 71% activity at 30 degrees C and 45% activity at 50 degrees C, up to 24 h. The enzyme activity was not inhibited by any of the metal ions tested except Hg2+, in the presence of which only 10% activity was retained.
The 35 kDa chitinase from Microbispora sp. V2 has an acidic pH optimum and a high temperature optimum. It is fairly stable and active, and degrades chitin efficiently, although the growth of the culture and enzyme production is slow.
This report is the first detailed study of a chitinase from Microbispora sp. V2, isolated from hot springs. The chitinase from Microbispora sp. V2 may have potential applications in the recycling of chitinous wastes, particularly due to its thermophilic and acidophilic character. Studies at molecular level may provide further insight on the chitinolytic system of Microbispora spp. with respect to the number and types of chitinases and their regulation.
纯化并鉴定来自小双孢菌属V2菌株的一种几丁质酶。
通过凝胶过滤色谱法将来自小双孢菌属V2菌株的几丁质酶纯化至同质，回收率为4.6%。其分子量为35 kDa，对对硝基苯基-β-D-N,N'-二乙酰壳二糖表现出最大活性，表明具有壳二糖酶活性。该酶的最适pH为3.0，最适温度为60℃。它在3.0至11.0的宽pH范围内稳定，在pH 3.0时保留61%的活性，在pH 11.0时保留52%的活性。在30℃下24小时内保留71%的活性，在50℃下保留45%的活性。除Hg2+外，所测试的任何金属离子均不抑制该酶活性，在Hg2+存在下仅保留10%的活性。
来自小双孢菌属V2菌株的35 kDa几丁质酶具有酸性最适pH和高温最适温度。它相当稳定且具有活性，能有效降解几丁质，尽管培养物生长和酶产生缓慢。
本报告是对从小温泉中分离出的小双孢菌属V2菌株的几丁质酶的首次详细研究。来自小双孢菌属V2菌株的几丁质酶可能在几丁质废物回收中具有潜在应用，特别是由于其嗜热和嗜酸特性。分子水平的研究可能会进一步深入了解小双孢菌属几丁质分解系统中几丁质酶的数量和类型及其调控。
