Enzyme-enzyme interactions within human erythrocytes as suggested from prelytic release.

The molecular sieving property of human erythrocyte membrane in slightly hypotonic media has been utilized for studying the intracellular localization of some proteins (Cseke et al., 1978, FEBS Lett. 96 15-18). It is now shown that four proteins which appear to be uniformly distributed within the cell behave similarly irrespective of the membrane resistance differences caused by changes of temperature and metabolic energy supply. Five enzymes catalyzing consecutive reactions in the glycolytic pathway between triosephosphate formation and lactate production are released from erythrocytes in quantities deviating from those predicted on the basis of molecular sieving. The data are compatible with the assumption that these enzymes form complexes with each other under in vivo conditions and that complex formation is facilitated if glycolysis is working at high rate (37 degrees C).