The purpose of this research is a comparative study of enzyme activity in semen of different animal species. The activity of Mg+2(Na++K+ )АТP-ase in plasma membranes of gametes of the bull and the ram showed no significant change in the process of cryopreservation of reproductive material. Identified specific features of the enzyme activities of plasma membranes of sperm cells, which are in reduced activity of this indicator in the membranes gametes of the cock as compared to that in the gametes of the bull, ram and boar. Defined cryogenic changes in the activity of membrane-bound enzyme Mg+2(Na++K+ )АТP-ase characteristic of reproductive cell membranes of the boar and the rooster. The relationship between the enzyme-substrate interaction, the concentration gradients of ions and separate stages of the technological process of the sperm of bull, ram, boar and rooster are a consequence of changes in the molecular organization of plasma membranes, the restructuring which is evident in the process of dilution, refrigeration, freezing and thawing of semen of animals