THE BINDING OF ETHACRYNIC ACID TO BOVINE SERUM ALBUMIN

Abstract

Studies with14C-labelled ethacrynic acid indicated that this potent diuretic binds to the albumin fraction of plasma protein. An investigation of the variation of molar binding as a function of the molar concentration ratio revealed that a mole of bovine serum albumin can bind 4 moles of ethacrynic acid strongly (probably irreversibly) and approximately 12 moles reversibly at pH 7.4. Further, it appears that the protein could accommodate a maximum of approximately 16 reversibly bound moles of ethacrynic acid at this pH. Efforts to determine the chemical identity of specific binding sites did not allow positive assignments.