INTERACTION OF RHODIUM(II) CARBOXYLATES WITH ENZYMES

  • 1 January 1976
    • journal article
    • research article
    • Vol. 36  (12) , 4402-4405
Abstract
The effect of rhodium(II) acetate, propionate and methoxyacetate on the activity of 17 enzymes was evaluated. The enzymes were preincubated with the Rh(II) complexes to detect irreversible inhibition. All enzymes that have essential sulfhydryl groups in or near their active site were irreversibly inhibited. Those enzymes without essential sulfhydryl groups were not affected. In each case, the rate of inactivation closely paralleled the observed toxicity and antitumor activity of rhodium(II) carboxylates; that is, rhodium(II) propionate > rhodium(II) acetate > rhodium(II) methoxyacetate. Those enzymes that were most sensitive to established sulfhydryl inhibitors, such as glyceraldehyde-3-phosphate dehydrogenase, were also most sensitive to rhodium(II) carboxylate inactivation. Proton NMR resonance measurements made during the titration of rhodium(II) acetate with cysteine showed that breakdown of the carboxylate cage occurred as a result of reaction with this sulfhydryl-containing amino acid. [These compounds show antitumor activity against L1210 leukemia and Ehrlich ascites tumors in mice.].