Studies of pyruvate-water isotope exchange catalysed by erythrocytes and proteins

Erythrocyte suspensions in buffer made with 2H2O catalyse the exchange of pyruvate protons. This process can be easly observed by spin-echo proton magnetic resonance. The dominant exchange process is shown to be due to the formation of Schiff-base links between pyruvate and amino groups of haemoglobin. Other proteins with free alpha-amino groups also catalyse the exchange. The pH*-dependence of the exchange rate due to hen-egg-white-lysozyme reflects the dissociation of the alpha-amino group.