3. (a) The activity of the Pentose Phosphate Pathway is commonly quantified by measuring 14CO2 production from C-14 labeled glucose. In this assay, glucose is metabolized aerobically by cells or tissue slices; both [1-14C] glucose and [6-14C] glucose are employed separately but in parallel. This classical method, thus, requires two separate assay mixtures. Which radioactive isotopomer of glu- cose releases 14 CO2 generated by the Pentose Phosphate Pathway? Confirm your conclusion by drawing the intermediates of the oxidative phase of the PPP with structural formulas, starting with glucose-6-phosphate. Name the intermediates and indicate enzymes. (b) ( Because the assay protocol requires aerobic incubation of cells or tis- sue slices with isotopically labeled glucose in parallel assays, what is the purpose of the other radioactive glucose derivative? To answer this question base your answer using the diagram on the right. O2 NADH CH₂OH + 2 NAD+ HO HO + 2 Pj 2 CO + 2 ATP HO OH 2 ADP CH3 + 2 H₂O Glucose Pyruvate (c) As you can appreciate from the above description of the classical assay system to measure the activity of the PPP, generating two assay systems that are exactly equivalent with respect to metabol- ic activity to be used in parallel is likely to be associated with many sources of experimental errors. For this reason, the doubly labeled glucose derivative [1,6-13 C2,6,6-2H2]glucose has been proposed as the probe molecule to measure PPP activity and glycolysis in only one incubation mixture because under anaerobic conditions glycolysis products are readily distinguished from PPP products. (c1) ( _) With respect to the diagram in Question 3(b) identify and draw the structures of the iso- topically enriched glycolytic products produced under anaerobic conditions. (c2) 6) Considering the products from the non-oxidative phase of the PPP that are returned to the glycolytic pathway, what are the products generated under anaerobic conditions starting from [1,6-13C2,6,6-2H2]glucose?

3. (a) The activity of the Pentose Phosphate Pathway is commonly quantified by measuring 14CO2 production from C-14 labeled glucose. In this assay, glucose is metabolized aerobically by cells or tissue slices; both [1-14C] glucose and [6-14C] glucose are employed separately but in parallel. This classical method, thus, requires two separate assay mixtures. Which radioactive isotopomer of glu- cose releases 14 CO2 generated by the Pentose Phosphate Pathway? Confirm your conclusion by drawing the intermediates of the oxidative phase of the PPP with structural formulas, starting with glucose-6-phosphate. Name the intermediates and indicate enzymes. (b) ( Because the assay protocol requires aerobic incubation of cells or tis- sue slices with isotopically labeled glucose in parallel assays, what is the purpose of the other radioactive glucose derivative? To answer this question base your answer using the diagram on the right. O2 NADH CH₂OH + 2 NAD+ HO HO + 2 Pj 2 CO + 2 ATP HO OH 2 ADP CH3 + 2 H₂O Glucose Pyruvate (c) As you can appreciate from the above description of the classical assay system to measure the activity of the PPP, generating two assay systems that are exactly equivalent with respect to metabol- ic activity to be used in parallel is likely to be associated with many sources of experimental errors. For this reason, the doubly labeled glucose derivative [1,6-13 C2,6,6-2H2]glucose has been proposed as the probe molecule to measure PPP activity and glycolysis in only one incubation mixture because under anaerobic conditions glycolysis products are readily distinguished from PPP products. (c1) ( _) With respect to the diagram in Question 3(b) identify and draw the structures of the iso- topically enriched glycolytic products produced under anaerobic conditions. (c2) 6) Considering the products from the non-oxidative phase of the PPP that are returned to the glycolytic pathway, what are the products generated under anaerobic conditions starting from [1,6-13C2,6,6-2H2]glucose?

Human Heredity: Principles and Issues (MindTap Course List)

11th Edition

ISBN:9781305251052

Author:Michael Cummings

Publisher:Michael Cummings

Chapter10: From Proteins To Phenotypes

Section: Chapter Questions

Problem 10QP: b. Compounds A, B, C, and D are known to be intermediates in the pathway for production of protein...

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