通过光散射强度测量研究辐射照射的溶菌酶水溶液中的二聚体形成。

Dimer formation in radiation-irradiated aqueous solution of lysozyme studied by light-scattering-intensity measurement.

作者信息

Hashimoto S, Seki H, Masuda T, Imamura M, Kondo M

出版信息

Int J Radiat Biol Relat Stud Phys Chem Med. 1981 Jul;40(1):31-46.

Abstract

The reaction of lysozyme with OH., Br.-2 and e-aq, produced in an aqueous solution by pulsed electrons and gamma-rays, were investigated. Irradiated enzymes showed an increase in the light scattering intensity (LSI) which is proportional to the absorbed dose. Results obtained from SDS gel electrophoresis confirm dimerization of lysozyme, which is considered to be responsible for the increase in LSI. It was found that the rate constant of the dimerization of protein radicals produced in the reaction with OH. is 2K=(1.0 +/- 0.3) X 10(6)M-1 s-1 and the yield of the dimerization is 0.6 in G. The enzymatic activity of the dimer is shown to be reduced to about 30 per cent of that of the intact enzyme. It is concluded that the radiation-induced inactivation of lysozyme is largely due to dimerization.

摘要

研究了溶菌酶与脉冲电子和γ射线在水溶液中产生的·OH、Br₂⁻和水合电子的反应。辐照后的酶表现出光散射强度（LSI）增加，且该增加与吸收剂量成正比。SDS凝胶电泳结果证实了溶菌酶的二聚化，这被认为是导致LSI增加的原因。研究发现，与·OH反应产生的蛋白质自由基的二聚化速率常数为2K = (1.0 ± 0.3)×10⁶ M⁻¹ s⁻¹，二聚化产率在G值中为0.6。二聚体的酶活性显示降低至完整酶活性的约30%。得出的结论是，辐射诱导的溶菌酶失活主要是由于二聚化。