[Interaction of platinum and palladium 5-sulfo-8-mercaptoquinoline complexes with sarcoplasmic reticulum Ca2+-dependent ATPase]. / O mekhanizme vzaimodeistviia 5-sul'fo-8-merkaptokhinolinovykh kompleksov platiny i palladiia s Ca2+-zavisimoi ATPazoi sarkoplazmaticheskogo petikuluma.

5-Sulfo-8-mercaptoquinoline complexes of platinum and palladium (complexes I and II) effectively inhibit Ca2+-dependent ATPase from sarcoplasmic reticulum. However, in contrast to K2PtCl4, K2PdCl4 and other previously investigated platinum and palladium complexes, they do not interact with the thiol groups of the enzyme. The inhibiting effects of complexes I and II are reversible and competitive with respect to ATP. In aqueous solutions complexes I and II decrease the fluorescence of tryptophane with a simultaneous shift in fluorescence towards the long-wave region. The same effect is exerted by the complexes on the fluorescence of tryptophane residues in Ca2+-dependent ATPase preparations. An addition of tryptophane to the enzyme preparations preincubated with complexes I and II partly restores the enzyme activity. It is assumed that the inhibiting effect of complexes I and II is due to their non-covalent interactions with the trytophane residues vicinal to the ATPase center.