Kinetic characteristics of Na+, K-ATPpase of Loach embryo cells

Abstract

The kinetic properties of the NA ⁺, K ⁺ -ATPase of embryos of the Loach Misgurnus fossilis L. were studied during early embryogenesis (from the stage of 2 blastomeres to stage 10 of blastomere separation). The dependence of the activity of NA ⁺, K ⁺ -ATPase of germ cells on the concentration of ATP is two-phase, practically at all studied stages of development, and this, in turn, is associated with an increase in the intensity of expression of enzyme molecules during embryonic development of embryos. The Michaelis-Menten constants for the ATP action of the NA ⁺, K ⁺ -ATPase of the plasma membrane of the embryos were calculated in Lineuiverk-Burk coordinates. According to the obtained K, the molecules of NA ⁺, K ⁺ -ATPase of germ cells during the studied stages of embryogenesis are characterized by catalytic centers with a low (2.7 mmol) affinity for ATP, the binding of the latter to these centers accelerates the catalytic cycle of molecules of membrane-bound enzymes of embryos. The obtained experimental data should be used to further clarify the molecular and membrane mechanisms of maintaining intracellular ionic homeostasis of embryos during embryogenesis