[Kinetics of 35S-lipoate binding in vitro by plasma proteins and formed elements of the blood].

When incubating isolated erythrocytes, leucocytes and blood plasma 35S-lipoate in rising concentrations (2.4-240 microng/ml) the intensive binding of the latter may be observed, that is 8-11% of 35S-lipoate total content in the incubation medium for proteins, 4.8-08% for erythrocytes and 1.1-0.12% for leucocytes. Calculating per 10(7) cells the binding of lipoate by leucocytes is 1-2 order higher than that by erythrocytes. In blood plasma binding of 35S-lipoate by leucocytes is 41-82% lower than in the physiological solution. The binding of lipoate by erythrocytes also drops in the presence of plasma as compared to the physiological solution, but this effect is less pronounced and significant only with the presence of 240 microng of lipoate per 1 ml of the medium. Kinetics of 35-S-lipoate binding by the blood cells is of complicated character and permits supposing the existence of the lipoate-barrier function of the plasmatic membranes which is able of regulating lipoate intake by erythrocytes up to a concentration of 24 microng/ml and by leucocytes even up to 240 microng/ml.