Activity of inosine triphosphate pyrophosphohydrolase in fresh and stored human erythrocytes.

The accumulation of inosine triphosphate (ITP) in human erythrocytes incubated with inosine depends on the activity of inosine triphosphate pyrophosphohydrolase (ITPH). High activity of this enzyme is accompanied by a low concentration of ITP and conversely. We showed that ITPH activity decreases with the prolongation of blood preservation time. As a consequence there is a lower accumulation of ITP in fresh erythrocytes incubated in a medium containing high concentrations of inosine, pyruvate and phosphate (IPP) than in red blood cells preserved at 4 degrees C. Synthesis of ITP in erythrocytes incubated in IPP medium being so intensive, it seems possible that during incubation an intermediate accumulates which decreases ITPH activity.