Kinetic analysis of 6-phosphogluconolactone hydrolysis in hemolysates

Hydrolysis of enzymatically generated 6-phosphogluconolactone in hemolysates has been found to be a first-order reaction, in all cases studied. It follows that the Michaelis constant of the reaction is higher than the highest 6-phosphogluconolactone concentration used in this study, viz., it is higher than 0.30 mmol l-1. The reaction first-order rate constant was found to decrease as the concentration, in the enzyme assay mixture, of the 6-phosphogluconolactone preparation was increased. It follows that this paradoxical effect may give rise to determinations involving spurious Michaelis constant and enzyme activity results. The possible causes of this effect are discussed.