Carnitine palmitoyl transferase I and the control of myocardial beta-oxidation flux.

Carnitine palmitoyltransferase I is assumed to be rate limiting for β-oxidation in all tissues. However, the concentration of malonyl-CoA in heart and muscle is high and is enough to completely inhibit β-oxidation if this assumption is correct. In this review, we consider whether: (i) there is a malonyl-CoA-insensitive carnitine palmitoyltransferase I activity; (ii) the measured malonyl-CoA concentration in the heart is physiologically meaningful; and (iii) carnitine palmitoyltransferase I is rate-limiting for β-oxidation in the heart.