Enzymes Helping Enzymes: Oxaloacetate Decarboxylase Increases Malate Dehydrogenase's Turnover Number

However, the maximal catalytic rates of enzymes differ up to hundred-fold between in vivo and in vitro measurements, suggesting that a complex chemical system has additional effects on catalytic performance.

In this work we show that the initial rate of an enzyme can increase three-fold due to the presence of a second enzyme, which uses the product of the first enzyme as its substrate. This enhancement may originate in an allosteric effect or result from binding competition for the product molecule by the second enzyme.