Interaction between Arginase and <scp>l</scp>‐Ornithine Carbamoyltransferase in <i>Saccharomyces cerevisiae</i>

Abstract

l ‐Ornithine carbamoyltransferase and arginase from Saccharomyces cerevisiae have been extensively purified and their quaternary structures have been determined by polyacrylamide gel electrophoresis in the presence of sodium dodecylsulfate. Subunit cross‐linking with glutaraldehyde shows that both enzymes have trimeric structures. Ornithine carbamoyltransferase is built up by the association of three subunits of molecular weight 37500; arginase is made of three subunits of 39000. The latter observation has lead us to reinvestigate the quaternary structure of rat liver arginase for which, in spite of an earlier report to the contrary [H. Hirsch‐Kolb and D. Greenberg, J. Biol. Chem. 243 , (1968) 6123–6129], evidence of a trimeric structure is also obtained. The data suggest that the 1‐to‐1 regulatory complex of ornithine carbamoyltransferase and arginase of S. cerevisiae , leading to ornithine carbamoyltransferase inhibition, is an hexamer.