摘要
用底物尿酸的紫外吸收变化跟踪反应,用单或双底物米氏方程和初速度估算苛求芽孢杆菌胞内尿酸酶最大反应速度,按Arrenius经验公式得到该尿酸酶在pH 9.2和pH 7.4的活化能,但这些活化不能解释其在两个pH下的催化活性差异.该酶同常见嘌呤衍生物氧嗪酸、黄嘌呤和尿酸有亲和力,但对尿酸亲和力最低,且亲和力与嘌呤衍生物解离成阴离子的能力相关.在生理条件下,该酶对尿酸的亲和力相对于最适条件有显著下降.据此推测,优化静电相互作用选择性增强该酶对尿酸的亲和力是提高其成药性的可能措施之一.
By monitoring the changes of UV absorbance of uric acid,the activation free energies of the intracellular uricase from Bacillus fastidiosus at pH 9.2 and pH 7.4 were estimated with Arrhenius equation,and the maximal reaction rates approximated from initial rates,but they can not account for the difference in the catalytic activity of this uricase under the two pH values.Among common purine derivatives,oxonate,xanthine and uric acid had affinities to this uricase,and uric acid had the lowest affinity.These affinities had some relationships to the dissociated constants of the tested compounds.Under physiological conditions,this uricase had a much weaker affinity for uric acid than that under the optimum conditions.It was proposed that the selective enhancement of the affinity of this uricase for uric acid over xanthine by engineering ionic interactions was possible to improve its pharmaceutical properties.
出处
《应用与环境生物学报》
CAS
CSCD
北大核心
2011年第1期91-94,共4页
Chinese Journal of Applied and Environmental Biology
基金
国家自然科学基金项目(Nos.30672009
81071427)
教育部新世纪优秀人才支持计划(No.NCET-09)~~
关键词
尿酸酶
嘌呤衍生物
尿酸
苛求芽孢杆菌
活化能
亲和力
uricase
purine derivatives
uric acid
Bacillus fastidiosus
activation free energy
affinity
