Turnover of Several Glycolytic Enzymes in Rabbit Heart, Soleus Muscle and Liver (original) (raw)

Turnover of glycogenolytic and glycolytic enzymes in rabbit liver, heart and soleus muscle was studied by means of single-pulse labelling with [ 14 C]leucine and isolation of the enzymes labelled /'// vivo by the immunochemical method. In liver, glyceraldehyde-phosphate dehydrogenase and lactate dehydrogenase turn over with apparent half-lives of 1.0 and 0.67 days. In heart and soleus muscle, phosphorylase, fructosebisphosphate aldolase, glyceraldehyde-phosphate dehydrogenase, enolase and lactate dehydrogenase reveal apparent half-lives in the range of 0.9 and. 1.2 days. The similarity of the degradation rates of these enzymes suggests that their different tissue levels result primarily from individual rates of synthesis. 6-Phosphofructokinase reveals a significantly higher degradation rate. The apparent half-lives in heart and soleus muscle are 0.43 and 0.67 days. The high turnover of 6-phosphofructokinase is discussed with regard to the regulatory role of this enzyme in glycolysis and possible mechanisms involved in degradation of the enzyme protein. Umsatzraten mehrerer glykolytischer Enzyme in Herz, Soleusmuskel und Leber des Kaninchens Zusammenfassung: Turnoverraten von Enzymen der Glykogenolyse und Glykolyse wurden nach einmaliger Pulsmarkierung mit [ 14 C]Leucin in Leber, Herz und m. soleus des Kaninchens bestimmt. Die in vivo markierten Enzymproteine wurden aus Gewebsextrakten mit Hilfe der Immunpräzipitation isoliert. Die scheinbaren Halbwertszeiten der Glycerinaldehydphosphat-Dehydrogenase und Lactat-Dehydrogenase betragen in der Leber l ,0 bzw. 0,67