Kim Aleksandr L, Musin Egor V, Dubrovskii Alexey V, Tikhonenko Sergey A
Institute of Theoretical and Experimental Biophysics Russian Academy of Science, Institutskaya st., 3, Puschino 142290, Moscow Reg., Russia.
Polymers (Basel). 2020 Apr 6;12(4):832. doi: 10.3390/polym12040832.
In this article, the effect of polyallylamine (PAA) on the structure and catalytic characteristics of alcohol dehydrogenase (ADH) was studied. For this research, we used methods of stationary kinetics and fluorescence spectroscopy. It has been shown that PAA non-competitively inhibits ADH activity while preserving its quaternary structure. It was established that 0.1 M ammonium sulfate removes the inhibitory effect of PAA on ADH, which is explained by the binding of sulfate anion (NH)SO with polyallylamine amino groups. As a result, the rigidity of the polymer chain increases and the ability to bind to the active loop of the enzyme increases. It is also shown that sodium chloride removes the inhibitory effect of PAA on ADH due to an electrostatic screening of the enzyme from polyelectrolyte. The method of encapsulating ADH in polyelectrolyte microcapsules was adapted to the structure and properties of the enzyme molecule. It was found that the best for ADH is its encapsulation by adsorption into microcapsules already formed on CaCO particles. It was shown that the affinity constant of encapsulated alcohol dehydrogenase to the substrate is 1.7 times lower than that of the native enzyme. When studying the affinity constant of ADH in a complex with PAA to ethanol, the effect of noncompetitive inhibition of the enzyme by polyelectrolyte was observed.
本文研究了聚烯丙胺(PAA)对乙醇脱氢酶(ADH)结构和催化特性的影响。本研究采用了稳态动力学和荧光光谱法。结果表明,PAA在保留其四级结构的同时非竞争性抑制ADH活性。已确定0.1 M硫酸铵可消除PAA对ADH的抑制作用,这是由于硫酸根阴离子(NH)SO与聚烯丙胺氨基结合所致。结果,聚合物链的刚性增加,与酶活性环结合的能力增强。还表明,氯化钠通过对酶进行聚电解质静电屏蔽而消除了PAA对ADH的抑制作用。将ADH封装在聚电解质微胶囊中的方法适应了酶分子的结构和性质。发现对ADH而言,最佳方法是通过吸附将其封装到已在CaCO颗粒上形成的微胶囊中。结果表明,包封的乙醇脱氢酶与底物的亲和常数比天然酶低1.7倍。在研究ADH与PAA形成的复合物对乙醇的亲和常数时,观察到了聚电解质对该酶的非竞争性抑制作用。