Case 1: Pyruvate Kinase (PK) catalyzes the rate-limiting, ATP-generating step of glycolysis in which phosphoenolpyruvate (PEP)...

Case 1: Pyruvate Kinase (PK) catalyzes the rate-limiting, ATP-generating step of glycolysis in which phosphoenolpyruvate (PEP) is converted to pyruvate. Multiple isoenzymes of pyruvate kinase exist in mammals: type L, which is found in the liver and kidneys; type R, which is expressed in erythrocytes; type M1, which is found in tissues such as muscle and brain; and type M2, which is present in self-renewing cells such as embryonic and adult stem cells. 1) Under normal conditions, describe all the ways in which pyruvate kinase is regulated in the cell? Many types of cancer cells are predominantly glycolytic and over express the oncoprotein MYC. Interestingly, the classical oncoprotein MYC has been found to promote preferential expression of pyruvate kinase type M2 over pyruvate kinase type M1. The isoform M2 is characteristically found in a low activity state and is ineffective at promoting glycolysis (When compared to pyruvate kinase type L or type M1). 2) This logic seems counter-intuitive for a glycolytic tissue. What is the rationale for this mechanism and what other pathways may cancer cells be diverting substrate to?

Expert Solution

gladiator answered 5 months ago

Hexokinase catalyzes the first step of glycolysis, in which glucose is phosphorylated to form glucose-6-phosphate. Which...

Hexokinase catalyzes the first step of glycolysis, in which glucose is phosphorylated to form glucose-6-phosphate. Which of the following statements are accurate? Choose all that apply. Hexokinase is found in the mitochondrial membrane. Hexokinase consists of two domains, or lobes, that come together when glucose and the MgATP2� complex are bound. Most kinases require the presence of a monovalent metal ion cofactor to prevent ATP hydrolysis. The conformational shift that occurs when glucose, but not water, enters the active site...

1. What is the major byproduct of anaerobic glycolysis: ATP, NADH, lactate, or pyruvate? 2. Glucose...

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1.) In the first step of glycolysis, the cell SPENDS an ATP and phosphorylates glucose as...

1.) In the first step of glycolysis, the cell SPENDS an ATP and phosphorylates glucose as soon as it enters the cell. Why does the cell do this? Give two reasons! 2.) Speculate on why glycolysis, which is the beginning point of many catabolic pathways does not require oxygen.

Substrate-level phosphorylation to yield ATP occurs during which stage(s) of aerobic respiration? A. glycolysis B. pyruvate...

Substrate-level phosphorylation to yield ATP occurs during which stage(s) of aerobic respiration? A. glycolysis B. pyruvate conversion to acetyl-CoA C. tricarboxylic acid cycle (Krebs cycle) D. fermentation E. A and B only F. A and C only G. B and C only H. A, B, C, and D

Which pathway reduces the most NAD+? 1. Glycolysis 2. Pyruvate Dehydrogenase Complex 3. Both Pyruvate Dehydrogenase...

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Which of the following reactions are catalyzed by kinases: Glycolysis 1,2,7,9; Pyruvate processing 1, citric acid...

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1. In fatty acid oxidation, ATP is consumed in which step? a. Transport of acyl CoA...

1. In fatty acid oxidation, ATP is consumed in which step? a. Transport of acyl CoA into the mitochondria b. Formation of the acyl-CoA c. Thiolysis of the ketoacyl- CoA intermediate d. Conversion of acyl-CoA into enoyl-CoA e. Formation of malonyl-CoA 2. If b-oxidation and citric acid cycle reactions completed the oxidation 3 molecules of hexanoic acid (6 carbon carboxylic acid) to CO2, how many CO2, NADH and FADH2 would be produced? (SHOW WORK) CO2 _______ NADH _______ FADH2 _______...

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