Enzyme inhibition in relation to chemotherapy.

Abstract

Summary1. The effect of enzyme concentration on the inhibition produced by certain inhibitors of the succinic dehydrogenase system has been experimentally determined. The inhibitors studied were malonate, itaconate, oxalacetate, quinone and cupric ion.2. The reaction between succinic dehydrogenase and copper or quinone was not immediate but required 30 to 40 minutes when the amount of inhibitor was just sufficient to produce complete inhibition.3. The effect of the strengths of binding of the inhibitor with the enzyme on the percent inhibition produced is shown to be related to the enzyme concentration.4. An expression has been developed which relates the velocity of reaction to enzyme concentration in enzyme-inhibitor systems.5. The results are discussed in relation to the chemotherapy of cancer. It is pointed out that the selective inhibition of an enzyme not unique to cancer tissue is theoretically possible.