[AMP-deaminase activity of circulating leukocytes in the human]

It is shown that the AMP-deaminase activity in leucocytes of the human peripheric blood in contrast with the enzyme from erythrocytes manifests its activity only if it is isolated in the presence of K+ or Na+ ions. Pi and GTP being inhibitors of the enzyme in different tissues including erythrocytes do not alter the AMP-deaminase activity in leucocytes. 3,3',5-triiodothyracetic acid markedly decreasing the AMP-deaminase activity of leucocytes does not affect the enzyme activity in the hemolyzate of erythrocytes. The results obtained have shown that the AMP-deaminase activity in leucocytes of the human peripheric blood possesses some regulatory properties differing from those of the enzyme in erythrocytes.