PCSIR Laboratories Complex Karachi, Karachi, Pakistan.
Pak J Pharm Sci. 2021 Jul;34(4):1333-1340.
Extra cellular β-galactosidase enzyme was purified and characterized from Aspergillus fumigatus PCSIR- 2013. Estimated molecular mass of the enzyme was approximately 95 kDa. by native polyacrylamide gel electrophoresis. Initially, different fermentation parameters were optimized for maximum production of β-galactosidase. The kinetic study of the partially purified enzyme exhibited that it remained active in broad range of temperature from 25°C to 70°C with an optimum of 60°C. The Km and Vmax were calculated as 9.95mmol/l and 51.78 U/ml/min, respectively. The optimum pH was 5.0, when reaction mixture was incubated for 30 min. The enzyme was very stable in the presence of different metal ions, although Na (16%) stimulates the activity at 10mM concentration. In contrast, Ba+2 and Hg have negative effect on enzyme activity and activity decreased to 54% and 19%, respectively. Thermo stability study was revealed that the enzyme retained 72% of its activity at 50°C. Whereas, when enzyme was incubated at 60°C for 120 min, its residual activity was decreased to 42.0%. However, the enzyme was completely inactivated at 80°C after 120 min of pre-incubation. Among different surfactant which incorporated with enzyme, Tween 20 and Triton X-100 both have stimulatory effect and activity increased to 29% and 17%, respectively.
从烟曲霉 PCSIR-2013 中纯化和表征了细胞外β-半乳糖苷酶。通过天然聚丙烯酰胺凝胶电泳，该酶的估计分子质量约为 95 kDa。最初，优化了不同的发酵参数以实现β-半乳糖苷酶的最大产量。部分纯化酶的动力学研究表明，该酶在 25°C 至 70°C 的宽温度范围内保持活性，最佳温度为 60°C。Km 和 Vmax 分别计算为 9.95mmol/L 和 51.78 U/ml/min。当反应混合物在 5.0 pH 下孵育 30 分钟时，酶的最适 pH 值为 5.0。该酶在存在不同金属离子的情况下非常稳定，尽管 Na（16%）在 10mM 浓度下刺激其活性。相比之下，Ba+2 和 Hg 对酶活性有负面影响，活性分别降低至 54%和 19%。热稳定性研究表明，该酶在 50°C 时保留了 72%的活性。然而，当酶在 60°C 下孵育 120 分钟时，其剩余活性降低至 42.0%。然而，在 120 分钟的预孵育后，该酶在 80°C 时完全失活。在与酶混合的不同表面活性剂中，Tween 20 和 Triton X-100 都具有刺激作用，活性分别增加到 29%和 17%。
