These were probed with anti-MCAD antibody or anti-SCAD antibody. Homozygous MCAD−/− mice had no detectable MCAD protein. MCAD protein is only detectable under the MCAD protein–spiked (positive control) lane. As a control analysis, liver homogenates probed with anti-SCAD antibody revealed that SCAD protein was present in both MCAD+/+ and MCAD−/− mice. No MCAD positive-control protein is detected by anti-SCAD antibodies (MCAD lane). mw, molecular weight standards.