Evidence for Catabolite Degradation in the Glucose‐Dependent Inactivation of Yeast Cytoplamic Malate Dehydrogenase

Abstract

The cytoplamic malate dehydrogenase of Sacchoromyces cerevisiae was radioactively labeled during its synthesis on a glucose‐free derepression medium. After purification a sensitive radio‐immunoassay for this enzyme could be developed. The assay showed that after the physiological, glucose‐dependent ‘catabolite inactivation’ of cytoplasmic malate dehydorgenase an inactive enzyme protein is immunologically not detchtable. Together with the irreversiblity of this reaction in vivo this finding strongly suggests a proteolytic mechanism of enzyme inactivation. For this process the term ‘catabolite degradation’ is used. Copyright © 1978, Wiley Blackwell. All rights reserved