[Biosynthesis of pyridoxal-5'-phosphate in lymphocytes stimulated by alloantigens in vitro].

Dynamics of alterations in pyridoxal kinase activity (key enzyme in biosynthesis of pyridoxal-5'-phosphate) was studied in lymphocytes of mice BALB/c, stimulated by irradiated cells from spleen of mice C3H in vitro. The cytolytic activity of lymphocytes was estimated by amount of Na251CrO4 realised from lysed cell-targets into medium. Maintenance of animals on a diet without pyridoxine within 1-3 weeks did not affect on the capacity of lymphocytes to proliferative in vitro and on their cytolytic activity. At the same time pyridoxal kinase activity was increased 2.5-3-fold in stimulated lymphocytes in presence of pyridoxal. Km value was 2.5-5.0.10(-5) M of pyridoxal for preparations of pyridoxal kinase from lymphocytes either with normal or with increased enzymatic activity. Lymphocytes of mice, kept on the diet without pyridoxine within 5-6 weeks, were characterized by distinctly decreased proliferative and cytolytic activities. Pyridoxal-5'-phosphate, added to incubation mixture in vitro, as distinct from pyridoxal, restored partially the impaired functions of T-lymphocytes.