TAILIEUCHUNG - Biochemistry, 4th Edition P77

Biochemistry, 4th Edition P77. Continuing Garrett and Grisham's innovative conceptual and organizing framework, "Essential Questions," BIOCHEMISTRY guides students through course concepts in a way that reveals the beauty and usefulness of biochemistry in the everyday world. Streamlined for increased clarity and readability, this edition also includes new photos and illustrations that show the subject matter consistently throughout the text. New end-of-chapter problems, MCAT practice questions, and the unparalleled text/media integration with the power of CengageNOW round out this exceptional package, giving you the tools you need to both master course concepts and develop critical problem-solving skills you can draw upon. | How Are Fatty Acids Synthesized 723 Levels of free fatty acids are very low in the typical cell. The palmitate made in this process is rapidly converted to CoA esters in preparation for the formation of triacylglycerols and phospholipids. Cells Must Provide Cytosolic Acetyl-CoA and Reducing Power for Fatty Acid Synthesis Eukaryotic cells face a dilemma in providing suitable amounts of substrate for fatty acid synthesis. Sufficient quantities of acetyl-CoA malonyl-CoA and NADPH must be generated in the cytosol for fatty acid synthesis. Malonyl-CoA is made by carboxylation of acetyl-CoA so the problem reduces to generating sufficient acetyl-CoA and NADPH. There are three principal sources of acetyl-CoA Figure 1. Amino acid degradation produces cytosolic acetyl-CoA. 2. Fatty acid oxidation produces mitochondrial acetyl-CoA. 3. Glycolysis yields cytosolic pyruvate which after transport into the mitochondria is converted to acetyl-CoA by pyruvate dehydrogenase. Inner mitochondrial Mitochondrial matrix membrane Cytosol FIGURE The citrate-malate-pyruvate shuttle provides cytosolic acetate units and some reducing equivalents electrons for fatty acid shuttle collects carbon substrates primarily from glycolysis but also from fatty acid oxidation and amino acid catabolism. Pathways that provide carbon for fatty acid synthesis are shown in blue pathways that supply electrons for fatty acid synthesis are shown in red. 724 Chapter 24 Lipid Biosynthesis Biotin carboxylase domain of human acetyl-CoA carboxylase 2 pdb id 2HJW The biotin carboxylase domain from human acetyl-CoA carboxylase 2 with the A-subdomain in blue the B-subdomain in red the A-B linker in green and the C-subdomain in yellow. The acetyl-CoA derived from amino acid degradation is normally insufficient for fatty acid biosynthesis and the acetyl-CoA produced by pyruvate dehydrogenase and by fatty acid oxidation cannot cross the mitochondrial membrane to participate directly in fatty .

• Sinh học
• Nền tảng của hóa sinh học
• trao đổi chất protein
• RNA trao đổi chất
• nguyên tắc của hóa sinh
• Axit amin
• công nghệ DNA