[Department of chemical kinetics].

Department of Biochemical Kinetics (headed by Kosterin S. A., Doctor of Biological Sciences) was founded in 1988. Research activity of the Department is mostly concerned with the biochemical mechanisms and dynamics of Ca2+ exchange in the smooth muscles, particular emphasis being laid on the examination of kinetic and catalytic properties of the membrane-linked energy-dependent Ca2+ transporting systems involved in regulation of intracellular Ca2+ concentration and control of the contractile behaviour of the smooth muscle cells. At present, the staff of the Department includes 2 doctors of sciences, 9 candidates of sciences and 6 technicians. Experimental data obtained at the Department since the date of its foundation provide new information concerning the energy-dependent Ca+ transporting systems of the smooth muscle cells, show the important role of Ca2+ pump of plasma membrane, endoplasmic reticulum and mitochondria as well as Na(+)-Ca2+ and Ca(2+)-H+ exchangers of sarcolemma in the regulation of Ca(2+)-exchange and mechanical activity of the smooth muscle. In the experiments performed on the inside-out vesicles derived from the sarcolemma of the myometrium the effect of quasi-stationary K(+)-diffusional membrane potential ("K(+)-valinomycin system") on the Mg2+, ATP-dependent Ca2+ transport was studied. It has been proved that the membrane potential (negative inside) stimulated the Mg2+, ATP-dependent transsarcolemmal transport of Ca2+ in the myometrium. The membrane potential stimulate maximal velocity of the Ca2+ pump leaving the affinity constant to the bivalent cation unaltered.(ABSTRACT TRUNCATED AT 250 WORDS)