FIGURE 3.

Mitochondrial synthesis of malonyl-CoA and its effect on CPT1b activity. Rat heart SSM and IFM were incubated for the indicated times in the presence of buffer only, buffer plus acetyl-CoA, and buffer containing all ACC substrates. At the indicated time points, malonyl-CoA content and CPT1b activity were determined as described under “Experimental Procedures.” Malonyl-CoA (closed symbols) is expressed as the micromolar concentration present in the CPT assay due to the addition of 10 μl of mitochondria preincubated with ACC substrates and CPT1b (open symbols) as nmol/min/mg mitochondrial protein. The values are the averages of three separate experiments.