金属离子Zn2+对精氨酸酶抑制作用的研究

摘要

The influence of Zn2+ on arginase catalyzed reaction was studied by microcalorimetry at 37°C ,pH = 9. 4,40 mmol · L-1 sodium barbiturate-hydrochloric acid buffer solution. The result indicated that Zn2+ has remarkable inhibition effect on the catalytic activity of arginase and the inhibitory type belongs to the reversible competitive inhibition with the inhibition constants of 6. 85xlCT7 mol · L-1. According to the inhibition type and ion radius,we suggest that the reason for inhibition is the competition of Zn 2+on the active site of arginase and thus inhibits the reaction activity of arginase.%在37℃,pH=9.4,40 mmol·L-1的巴比妥钠-盐酸缓冲体系中,利用微量热法研究了金属离子Zn2+对牛肝精氨酸酶催化L-精氨酸水解反应的影响.实验表明,Zn2+对精氨酸酶催化反应存在着明显抑制作用,其抑制类型为竞争性可逆抑制,并求得抑制常数K1为6.85×10-7 mol·L-1.根据其抑制类型和离子半径,推测Zn2+对精氨酸酶的抑制主要是夺取Mn2+的位置,从而使酶失活.