The reaction of metallothionein with mercuribenzoate. A dialysis and 113Cd-n.m.r. study.

摘要: Reaction of rat liver cadmium-metallothionein-II(Cd-MT-II) with p-hydroxymercuribenzoate(pHOHgBzO-) causes displacement bound Cd. When pHOHgBzO- -induced 109Cd is observed after dialysis the reaction mixture, stoichiometry consistent stepwise tetraco-ordinate Cd atoms by non-random entry reagent into polynuclear clusters. 113Cd n.m.r. allows direct observation effects on titration 113Cd-MT-II pHOHgBzO-. The first equivalent reduces all resonances approximately equally. Subsequently differential reactivity protein thiolates towards gives rise to decreases in signal intensities. Resonances previously attributed a three-metal cluster are lost before those arising from four-metal cluster. These results interpreted terms current models MT structure. They distinct 5,5'-dithiobis-(2-nitrobenzoic acid), which distinguishes between only two classes thiolates, terminal and bridging. Such different patterns may underlie biological activity this protein.