This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Howard, R. A. Articles by Bear, J. L. Search for Related Content PubMed PubMed Citation Articles by Howard, R. A. Articles by Bear, J. L.

The Interaction of Rhodium(II) Carboxylates with Enzymes

Departments of Chemistry [J. L. B.] and Biophysical Sciences [R. A. H., T. G. S.], University of Houston, Houston, Texas 77004

The effect of rhodium(II) acetate, propionate, and methoxyacetate on the activity of 17 enzymes was evaluated. The enzymes were preincubated with the rhodium(II) complexes in order to detect irreversible inhibition. All enzymes that have essential sulfhydryl groups in or near their active site were found to be 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. In addition, those enzymes that have been demonstrated to be most sensitive to established sulfhydryl inhibitors, such as glyceraldehyde-3-phosphate dehydrogenase, were also most sensitive to rhodium(II) carboxylate inactivation. Proton nuclear magnetic 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.

¹ Recipient of Grant GM-20479 from the NIH.

² Recipient of Grant CA-13817 from the NIH. To whom requests for reprints should be addressed, at the Department of Chemistry, University of Houston, Houston, Texas 77004.

Received 5/21/76. Accepted 8/23/76.