[Interaction of platinum and palladium complexes with thiol groups of Ca2+-dependent ATPase from sarcoplasmic reticulum].

In native preparations of sarcoplasmic reticulum 10-12 thiol groups (in g-eqv per 10(5) g of protein) were estimated by the Benesh method (titration with AgNO3) and 2 thiol groups--by Ellman (titration with dithionitrobenzoic acid). After denaturation of the sarcoplasmic reticulum preparations with 8 M urea 10-12 thiol groups were also determined by the Ellman method. When the preparations were treated with platinum tetrachloride or with palladium diaminodichloride, only 3 thiol groups were estimated by the Benesh and no one - by the Ellman method. Platinum and palladium complexes inhibited also the Ca2+-dependent activity blocking the transport of Ca2+ in sarcoplasmic reticulum. The inhibition was partially removed by glutathione.