Ebook BRS Biochemistry, molecular biology and genetics (5th edition): Part 2
➤ Gửi thông báo lỗi ⚠️ Báo cáo tài liệu vi phạmNội dung chi tiết: Ebook BRS Biochemistry, molecular biology and genetics (5th edition): Part 2
Ebook BRS Biochemistry, molecular biology and genetics (5th edition): Part 2
https://khothuvien.cori!chapter11Ketones and Other Lipid DerivativesI.KETONE BODY SYNTHESIS AND UTILIZATION (FIGURE 11-1)A. Synthesis of ketone bodies Ebook BRS Biochemistry, molecular biology and genetics (5th edition): Part 2s (Figure 11-1, top) occurs in liver mitochondria when fatty acids are in high concentration in the blood (during fasting, starvation, or as a result of a high-fat diet).1Ịi-Oxidation produces NADH and adenosine triphosphate (ATP) and results in the accumulation of acetyl coenzyme A (CoA), owing to Ebook BRS Biochemistry, molecular biology and genetics (5th edition): Part 2allosteric inhibition of tricarboxylic acid (TCA) cycle enzymes. The liver is also producing glucose using oxaloacetate (OAA), so there is decreased cEbook BRS Biochemistry, molecular biology and genetics (5th edition): Part 2
ondensation of acetyl CoA with OAA to form citrate.2Two molecules of acetyl CoA condense to produce acetoacetyl CoA. This reaction is catalyzed by thihttps://khothuvien.cori!chapter11Ketones and Other Lipid DerivativesI.KETONE BODY SYNTHESIS AND UTILIZATION (FIGURE 11-1)A. Synthesis of ketone bodies Ebook BRS Biochemistry, molecular biology and genetics (5th edition): Part 2e.4HMG-CoA is cleaved by HMG-CoA lyase to form acetyl CoA and acetoacetate.5Acetoacetate can be reduced by an NAD-requiring dehydrogenase (3-hydroxybutyrate dehydrogenase) to 3-hydroxybutyrate (also known as p-hydroxybutyrate). This is a reversible reaction.6Acetoacetate is also spontaneously decarb Ebook BRS Biochemistry, molecular biology and genetics (5th edition): Part 2oxylated in a nonenzymalic reaction, forming acetone (the source of the odor on the breath of ketotic diabetic patients).CLINICAL ggCORRELATESType 1 dEbook BRS Biochemistry, molecular biology and genetics (5th edition): Part 2
iabetes mellitus is due to a deficiency of insulin, which is caused by autoimmune destruction 0Í insulin-producing cells in the pancreas. Insulin is rhttps://khothuvien.cori!chapter11Ketones and Other Lipid DerivativesI.KETONE BODY SYNTHESIS AND UTILIZATION (FIGURE 11-1)A. Synthesis of ketone bodies Ebook BRS Biochemistry, molecular biology and genetics (5th edition): Part 2 serum glucose level, increased ketone body synthesis, and formation of acetone due to decarboxylation of acetoacetate.7Tile liver lacks the enzyme needed to metabolize ketone bodies (succinyl CoA-acetoacetate-CoA transferase, a thiotransferase), so it cannot use the ketone bodies it produces. There Ebook BRS Biochemistry, molecular biology and genetics (5th edition): Part 2fore, acetoacetate and 3-hydroxybutyrate are released into the blood by the liver.B. Utilization of ketone bodies (Figure 11-1, bottom)1When ketone boEbook BRS Biochemistry, molecular biology and genetics (5th edition): Part 2
dies are released from the liver into the blood, they are taken up by peripheral tissues such as muscle and kidney, where they are oxidized for energyhttps://khothuvien.cori!chapter11Ketones and Other Lipid DerivativesI.KETONE BODY SYNTHESIS AND UTILIZATION (FIGURE 11-1)A. Synthesis of ketone bodies Ebook BRS Biochemistry, molecular biology and genetics (5th edition): Part 2enter cells directly, or it can be produced from the oxidation of 3-hydroxybu-tyrate by 3-hydroxybutyrate dehydrogenase. NADH is produced by this reaction and can generate adenosine triphosphate (ATP).3Acetoacetate is activated by reacting with succinyl CoA to form acetoacetyl CoA and succinate. The Ebook BRS Biochemistry, molecular biology and genetics (5th edition): Part 2 enzyme is succinyl CoA-acetoacetate-CoA transferase (a thiotransferase).4Acetoacetyl CoA is cleaved by thiolase to form two molecules of acetyl CoA,Ebook BRS Biochemistry, molecular biology and genetics (5th edition): Part 2
which enter the TCA cycle and are oxidized to molecules of co2.163164 Biochemistry, Molecular Biology, and GeneticsK«ton« Body SyntbotltLiver mitochonhttps://khothuvien.cori!chapter11Ketones and Other Lipid DerivativesI.KETONE BODY SYNTHESIS AND UTILIZATION (FIGURE 11-1)A. Synthesis of ketone bodies Ebook BRS Biochemistry, molecular biology and genetics (5th edition): Part 2ate; HMG-CoA, hydroxymethylglutaryl coenzyme A; OAA, oxaloacetate; TCA, tricarboxylic acid. The thiotransferase is succinyl CoA-acetoacetate-CoA transferase.5Energy is produced from the oxidation of ketone bodies.a.One acetoacetate produces two acetyl CoA, each of which can generate about 10 ATP, or Ebook BRS Biochemistry, molecular biology and genetics (5th edition): Part 2 a total of about 20 ATP via the TCA cycle.b.However, activation of acetoacetate results in the generation of one less A TP because guanosine triphospEbook BRS Biochemistry, molecular biology and genetics (5th edition): Part 2
hate (GT p), the equivalent of ATP, is not produced when succinyl CoA is used to activate acetoacetate. (In the TCA cycle, when succinyl CoA formsKetohttps://khothuvien.cori!chapter11Ketones and Other Lipid DerivativesI.KETONE BODY SYNTHESIS AND UTILIZATION (FIGURE 11-1)A. Synthesis of ketone bodies Ebook BRS Biochemistry, molecular biology and genetics (5th edition): Part 2hydroxybutyrate is oxidized, 2.5 additional ATP are formed because tile oxidation of 3-hydroxybutyrate to acetoacetate produces NADH.II.PHOSPHOLIPID AND SPHINGOLIPID METABOLISMA. Synthesis and degradation of phosphoglycerides1The phosphoglycerides an: synthesized by a process similar ill ils initial Ebook BRS Biochemistry, molecular biology and genetics (5th edition): Part 2 steps Io triacylglycerol synthesis (glycerol 3 phosphate combines with two fatty' acyl CoA to form phosphatidic acid).2Synthesis of phosphatidylinosiEbook BRS Biochemistry, molecular biology and genetics (5th edition): Part 2
tola.Phosphatidic acid reacts with cytidine triphosphate (CTP) to form cytidine diphosphate (CDP)-diacylglycerol, which reacts with inositol to form phttps://khothuvien.cori!chapter11Ketones and Other Lipid DerivativesI.KETONE BODY SYNTHESIS AND UTILIZATION (FIGURE 11-1)A. Synthesis of ketone bodieshttps://khothuvien.cori!chapter11Ketones and Other Lipid DerivativesI.KETONE BODY SYNTHESIS AND UTILIZATION (FIGURE 11-1)A. Synthesis of ketone bodiesGọi ngay
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