Scarf A R, Cole E R, Southwell-Keely P T
Biochem J. 1982 Feb 1;201(2):305-9. doi: 10.1042/bj2010305.
Potassium benzyl selenosulphate and potassium p-nitrobenzyl selenosulphate were shown to be powerful inhibitors of the thiol-dependent enzymes glutathione reductase and papain, but to have no effect on the serine-dependent proteinase trypsin. By contrast, potassium benzyl thiosulphate and potassium p-nitrobenzyl thiosulphate, at much higher concentrations, have virtually no effect on any of the enzymes. The selenosulphates show characteristics of both reversible non-competitive and irreversible inhibition. On the basis of model reactions in which the selenosulphates react instantly with cysteine, it is suggested that they form labile selenosulphide derivatives with the enzymes, but that these derivatives may be broken down either by the normal functioning of the enzyme (in the case of glutathione reductase) or by the approaching substrate (in the case of papain). Continued inhibition of the enzymes requires a stoicheiometric excess of inhibitor over enzyme.
苄基硒代硫酸盐钾和对硝基苄基硒代硫酸盐钾被证明是硫醇依赖性酶谷胱甘肽还原酶和木瓜蛋白酶的强效抑制剂，但对丝氨酸依赖性蛋白酶胰蛋白酶没有影响。相比之下，苄基硫代硫酸盐钾和对硝基苄基硫代硫酸盐钾在高得多的浓度下，对任何一种酶几乎都没有影响。硒代硫酸盐表现出可逆非竞争性和不可逆抑制的特征。基于硒代硫酸盐与半胱氨酸立即反应的模型反应，表明它们与酶形成不稳定的硒代硫化物衍生物，但这些衍生物可能通过酶的正常功能（在谷胱甘肽还原酶的情况下）或接近的底物（在木瓜蛋白酶的情况下）分解。持续抑制酶需要抑制剂相对于酶有化学计量过量。
