摘要
核酸酶P_1(EC 3.1.30)是一个具有水解核酸(RNA和DNA)功能的含锌金属酶,其水解产物是组成RNA或DNA的结构单元——四种5’-核苷单磷酸或四种5’-脱氧核苷单磷酸. 金属离子在一定的条件下,可能与酶、核酸或核苷酸形成配合物,从而影响酶催化的水解核酸反应.
The effects of metal ions Zn2+, Mg2+, Mn2 + , Ti3+, Fe2 + , Co2+ Cu2+, Pd2+ and Ce3+ on catalytic hydrolysis of RNA by ribonucleic acid enzyme P1 have been investigated. It was found that most transition metal ions are inhibitors, but Zn2+ is activator and Mg2+ shows no effect on the reaction. The inhibition constants (Ki) of Fe2+, Co2+ and Cu2+ are 16.8, 18.5 and 14.8 mmol/L respectively. The ESR spectrum of the reaction product of Cu2 + with RNA was determined, the result showed that a Cu-RNA complex is possibly formed. The mechanism of the inhibition effect of metal ions on catalytic hydrolysis of RNA was discussed. It was considered that the inhibition is due to the formation of metal--RNA complex.
