Thakur Shikha, Sharma Nirmal Kant, Thakur Neerja, Bhalla Tek Chand
Department of Biotechnology, Himachal Pradesh University, Summer Hill, Shimla, Himachal Pradesh, 171005, India.
3 Biotech. 2016 Dec;6(2):180. doi: 10.1007/s13205-016-0500-0. Epub 2016 Aug 26.
Proteases are a class of enzymes that catalyze hydrolysis of peptide bonds of proteins. In this study, 221 proteolytic bacterial isolates were obtained by enrichment culture method from soils of various regions of Himachal Pradesh, India. From these a hyper producer of protease was screened and identified by morphological and physiological testing and by 16S rDNA sequence as Serratia marcescens PPB-26. Statistical optimization of physiochemical parameters enhanced the protease production by 75 %. Protease of S. marcescens PPB-26 was classified as a metalloprotease. It showed optimal activity at 30 °C, pH 7.5 (0.15 M Tris-HCl buffer) and with 0.8 % substrate concentration. It had K = 0.3 %, V = 34.5 μmol min mg protein and a half life of 2 days at 30 °C. The enzyme was stable in most metal ions but showed increased activity with Fe and Cu while strong inhibition with Co and Zn. Further investigation showed that the enzyme could not only retain its activity in various organic solvents but also showed increased activity with methanol and ethanol. The reported metalloprotease is thus a potential candidate for carrying out industrial peptide synthesis.
蛋白酶是一类催化蛋白质肽键水解的酶。在本研究中，通过富集培养法从印度喜马偕尔邦不同地区的土壤中获得了221株产蛋白水解酶的细菌分离株。从中筛选出一株蛋白酶高产菌株，并通过形态学和生理学测试以及16S rDNA序列鉴定为粘质沙雷氏菌PPB - 26。对理化参数进行统计优化后，蛋白酶产量提高了75%。粘质沙雷氏菌PPB - 26的蛋白酶被归类为金属蛋白酶。它在30°C、pH 7.5（0.15 M Tris - HCl缓冲液）和0.8%底物浓度下表现出最佳活性。其米氏常数K = 0.3%，最大反应速度V = 34.5 μmol min mg蛋白，在30°C下半衰期为2天。该酶在大多数金属离子中稳定，但在铁和铜存在时活性增加，而钴和锌则对其有强烈抑制作用。进一步研究表明，该酶不仅能在各种有机溶剂中保持活性，而且在甲醇和乙醇存在时活性增加。因此，报道的这种金属蛋白酶是进行工业肽合成的潜在候选酶。
