MCB 450 1st Edition Lecture 17Outline of Last Lecture I. Glucose can be synthesized from noncarbohydrate precursorsII. Gluconeogenesis and glycolysis are reciprocally regulatedIII. The Cori cycleIV. Purpose of the Pentose Phosphate Pathway (PPP)V. Oxidative phaseVI. Nonoxidative phaseVII. Balancing the cellular needs for ATP, NADPH and ribose-5-POutline of Current Lecture I. Overview of the process of complete oxidation of glucose (glycolysis + TCA Cycle + Oxidative Phophorylation)II. Preparatory step for TCA Cycle (Pyruvate Acetyl CoA)III. Reactions of the TCA Cycle (8)IV. Regulation of the TCA CycleV. TCA Cycle can also provide precursors for biosynthesisVI. Anaplerotic reactionsVII. The glycoxylate cycle Current LectureThe activation of protein kinase A by a G-protein pathway-Adenylate cyclase is responsible for converting ATP to cyclic AMP-Insulin binds its own receptorGluconeogenesis precursors-Fatty acids cannot be used to make glucose but glycerol can -Lactate comes from anaerobic glycolysis in the musclesFate of Pyruvate under Anaerobic conditions in animals and other microorganisms: lactic acid fermentation-Pyruvate is a more reduced form than lactate-The reaction from glucose 6-phosphate to 6-phosphoglucono-alpha-lactone is allosterically regulated by NADPHIsomerization-Ribose 5-phosphat is a nucleic acidThe nonoxidative phase includes three other reactions-Don't lose any carbons, they are just shuffled around-This reaction is reversibleThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.Transketolase-Both F6P and GAP are intermediates of glycolysisThe NADPH and ribose 5-phosphate needs are balanced. -No need for the nonoxidative phaseTCA Cycle-Occurs in the matrix of the mitochondria-8 reactions in the TCA cycle-Only other organelle that has two membranes besides the mitochondria is the nucleus-The outer membrane is very permeable-ATP-phosphatase enzymes are embedded in the inner mitrochrondial membrane-Inner membrane is not very permeableThe Decisive Step-Pyruvate Dehydrogenase Complex-Pyruvate is made in the cytoplasm and then transported into the inner mitochondrial matrix-TPP -- thiamine pyrophosphatePyruvate Dehydrogenase Complex uses three catalytic coenzymes (prosthetic groups)-Lipoic acid is the oxidized formThe synthesis of acetyl CoA pyruvate consists of three steps:-First two steps done by E1 and third step is done by E2Step 1: Decarboxylation (E1)-Carbanion of TPP -- (Thiazole ring acts as a nucleophile)Step 2: Oxidation (E1)-Lipoamide is bound to E2oBut will be moved to active site of E1Slide 22 & 23-High energy stimulates kinaseoNADH, Acetyl CoAoHigh levels of these will turn up the kinaseoNAD+, HS-CoA, ADP, Pyruvate will turn off the kinase-NAD+, Ca2+ and HS-CoA affects H2O to PioLow energy stimulates phosphotaseThe TCA Cycle-The TCA Cycle is an amphibolic pathwayTwo Phases of TCA-Succinyl CoA is a high energy thioester
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