Site of participation of cytochrome b5 in hepatic microsomal fatty acid chain elongation. Electron input in the first reduction step.

摘要: Abstract The present study provides strong evidence for the involvement of rat liver microsomal cytochrome b5 in first reduction step fatty acid chain elongation. rate reoxidation NADH-reduced was markedly stimulated (up to 3-fold) by addition increasing concentrations beta-ketohexadecanoyl-CoA (1-8 microM). A quantitative analysis product formation, effect cyanide, and anaerobiosis completely exclude possibility that desaturase activity accounted beta-ketohexadecanoyl-CoA-induced stimulation rate. Using microsomes from untreated rats, beta-keto substrate found stimulate 30%. However, when fat-free diet rats were employed more than 3-fold, suggesting beta-ketoacyl-CoA reductase is inducible a high carbohydrate, diet. This also noninvolvement terminal reaction (second elongation), which catalyzed trans-2-enoyl-CoA reductase. Although trans-2-hexadecenoyl-CoA significantly under aerobic conditions, it did not have any stimulatory anaerobic conditions. One interpretation these results delta 9 system. Consistent with this conclusion fact inhibited desaturation stearoyl-CoA oleoyl-CoA.