Enzyme activity was analyzed in mouse liver homogenates using the electron transport flavoprotein (ETF) reduction assay with octanoyl-CoA (C8:0) and palmitoyl-CoA (C16:0) as substrates. MCAD−/− mice had a significant reduction in ability to dehydrogenate octanoyl-CoA and a modest reduction in activity toward palmitoyl-CoA compared to MCAD+/+ mice (Table 1). Specifically, the dehydrogenation of octanoyl-CoA and palmitoyl-CoA substrates were reduced by 75% and by 30%, respectively, in MCAD−/− mice as compared to MCAD+/+ controls.