Biochemistry 2288A Lecture Notes - Lecture 12: Mitochondrial Matrix, Triglyceride, Glycerol
17 Jun 2016
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Carbohydrates are not the only source of acetyl-coa for the citric acid cycle. Fatty acids from stored triacylglycerol or from the diet can be degraded and oxidized to acetyl-coa. When energy is needed from fat storage, lipases in adipocytes degrade triacylglycerol into glycerol and three fatty acids. The released fatty acids enter the bloodstream and are used as fuel in other cells, such as skeletal muscle, heart, and liver. The released glycerol is a substrate for gluconeogenesis. In a cell that is using fatty acids for fuel, specific transporters move fatty acid from the blood into the cytosol. Then, the fatty acid is activated with coa in the cytosol in a reaction that is driven by hydrolysis of atp to amp and ppi. The resulting acyl-coa is transported into the mitochondrial matrix. There, the acyl-coa is oxidized in a series of four chemical reactions (fig. Each set of reactions removes two carbons from the fatty acid chain as acetyl-
