Fopase Rushikesh, Nayak Suman, Mohanta Monalisha, Kale Paresh, Paramasivan Balasubramanian
1Department of Biotechnology and Medical Engineering, National Institute of Technology Rourkela, Odisha, 769008 India.
2Department of Electrical Engineering, National Institute of Technology Rourkela, Odisha, 769008 India.
3 Biotech. 2019 Apr;9(4):124. doi: 10.1007/s13205-019-1661-4. Epub 2019 Mar 6.
The present work describes the inhibition studies of free as well as immobilized urease by different heavy metals. Porous silicon (PS) films prepared by electrochemical etching were used for urease immobilization by physical adsorption. The enzyme was subjected to varying concentrations of Cr, Cr, Cu, Fe, Cd and Ni and analyzed for the variation in the activity. To study the effect of other heavy metals on the interaction of urease and Cr, free as well as immobilized urease was subjected to the combination of each metal ion with Cr. Results proved the sensitivity of free as well as immobilized urease towards heavy metals by observed reduction in activity. Immobilized urease showed less degree of inhibition compared to free urease when tested for inhibition by individual metal ions and in combination with Cr. IC values were found higher for inhibition by the combination of metal ions with Cr. Interaction of heavy metal ions with functional groups in active site of urease and limitations of mass transfer are the two factors responsible for the variation in activity of urease. Relation between the variation of urease activity and amount of heavy metals can be applied in biosensor development for determining the concentration of Cr present in the water samples.
本研究描述了不同重金属对游离脲酶和固定化脲酶的抑制作用。采用电化学蚀刻制备的多孔硅（PS）薄膜通过物理吸附法固定脲酶。将脲酶置于不同浓度的铬、铜、铁、镉和镍中，并分析其活性变化。为了研究其他重金属对脲酶与铬相互作用的影响，将游离脲酶和固定化脲酶分别置于每种金属离子与铬的组合中。结果表明，通过观察到的活性降低，游离脲酶和固定化脲酶对重金属均敏感。当分别用单个金属离子以及与铬组合进行抑制测试时，固定化脲酶的抑制程度低于游离脲酶。发现金属离子与铬组合的抑制作用的半数抑制浓度（IC）值更高。重金属离子与脲酶活性位点官能团的相互作用以及传质限制是导致脲酶活性变化的两个因素。脲酶活性变化与重金属含量之间的关系可应用于生物传感器开发，以测定水样中铬的浓度。
