Studies on the mechanism of protection by aurintricarboxylic acid in beryllium poisoning. II. Equilibria involving alkaline phosphatase.

It has been demonstrated (1) that aurintricarboxylic acid (ATA) reverses beryllium-induced inhibition of plasma alkaline phosphatase both in vitro and in vivo. It was suggested (2) that the ability of ATA to reverse the enzymatic and toxicological properties of Be++ involves chelate formation between Be++ and the ortho carboxyl, hydroxyl groups in the ATA molecule and the concomitant formation of a non-diffusible, colloidal lake. The enzymatic reactions involving Be++ and ATA, or smaller molecules possessing the same functional groups as ATA, furnish a means of quantitatively measuring the stabilities of the various chelates and the binding between the enzyme and the organic molecule. The present report describes the results of investigations of the reactions among plasma alkaline phosphatase, Be++, and the 3 molecules shown.