Pyruvate carboxylation in the rat heart. Role of biotin-dependent enzymes.
Pyruvate carboxylation in the isolated perfused rat heart was studied under steady-state conditions. A biotin deficiency resulting in a 90% decrease in myocardial pyruvate carboxylase left the pyruvate carboxylation rate unchanged. Pyruvate carboxylation in heart muscle must therefore take place by means of an enzyme which does not contain biotin. The kinetic properties and mass-action ratio of the NADP-linked malic enzyme in heart muscle can be taken as circumstantial evidence in favour of the role of malic enzyme in pyruvate carboxylation in myocardium.
Sundqvist
K E
KE
Department of Medical Biochemistry, University of Oulu, Finland.
Hiltunen
J K
JK
Hassinen
I E
IE
D000818:Animals; D002262:Carboxy-Lyases / Q000378:metabolism*; D005260:Female; D007700:Kinetics; D008025:Ligases / Q000378:metabolism*; D008291:Malate Dehydrogenase / Q000378:metabolism; D009206:Myocardium / Q000378:metabolism*; D011766:Pyruvate Carboxylase / Q000378:metabolism; D011773:Pyruvates / Q000378:metabolism*; D019289:Pyruvic Acid; D051381:Rats; D011919:Rats, Inbred Strains
D011773:Pyruvates; D019289:Pyruvic Acid; D008291:Malate Dehydrogenase; D002262:Carboxy-Lyases; D008025:Ligases; D011766:Pyruvate Carboxylase