Properties of Tissue-Nonspecific Alkaline Phosphatase from Mammalian Testes

The enzyme systems of living organisms catalyse biochemical reactions and are an important component of the functioning of organs and systems. Alkaline phosphatase is localised on the plasma membranes of cells and catalyses the hydrolysis of the phosphoester bond. This enzyme is found in liver, bone, kidney, intestine, placenta and many other organs and tissues. Levels of alkaline phosphatase activity can be altered in various diseases. Despite the universality of the mechanism of action, the function of alkaline phosphatase is poorly understood. Characteristics of alkaline phosphatase isoenzymes, both tissue-specific and tissue-specific: intestinal, germinal, placental. The analysis of literature data on the study of tissue-specific alkaline phosphatase function in bone calcification, in the accumulation of triglycerides by adipose tissue cells, in embryonic development and in spermatogenesis is performed. This review presents an analysis of data on the localisation of alkaline phosphatase in mammalian testes. Alkaline phosphatase was detected in the peritubular cells of the seminiferous tubules and in spermatogonia. Weak reactivity to alkaline phosphatase was observed in Sertoli cells. The enzyme is species-specific: it has been detected in the testes of rats, mice, dogs, guinea pigs, and human testes. Hamsters, rabbits, and bats do not express alkaline phosphatase. The molecular structure of alkaline phosphatase and its properties in relation to standard inhibitors have been characterised. However, the effect of the enzyme on the differentiation of primary germ cells and on the maturation of spermatogenesis cells in mammalian testes has not been studied. Further studies are needed to determine the role of alkaline phosphatase in the physiology of cells and tissues of the reproductive system, including germ cell meiosis.