(a)
Interpretation:
6-phosphoglucono-⏹-lactone should be identified.
Concept introduction:
6-phosphoglucono-⏹-lactone is formed during the pentose phosphate pathway. In the first step of pentose phosphate pathway, dehydrogenation of glucose-6-phosphate at C-1 takes produce 6-phosphoglucono-⏹-lactone.
Answer to Problem 28P
The compound C in the reaction is 6-phosphoglucono-⏹-lactone.
Explanation of Solution
6-phosphoglucono-⏹-lactone is an intramolecular ester formed by the reaction of C-1 carboxyl group and C-5 hydroxyl group. It is formed by dehydrogenation of C-1 carbon of Glucose-6-phosphate. Hydroxyl group at C-1 of glucose-6-phosphate is converted to carbonyl group. Therefore, the structure of 6-phosphoglucono-⏹-lactone is (C).
(b)
Interpretation:
The reactions producing NADPH should be determined.
Concept introduction:
Two molecules of NADPH are produced duringthe oxidative phase of pentose phosphate pathway.
Answer to Problem 28P
The reactions B and F produce NADPH.
Explanation of Solution
First NADPH is produced when the C-1 in glucose-6-phosphate is dehydrogenated into 6-phosphoglucono-⏹-lactone by glucose-6-phosphate dehydrogenase. This 6-phosphoglucono-⏹-lactone is hydrolyzed by a lactonase resulting 6-phosphogluconate. This 6C sugar acid is then decarboxylated by 6-phosphogluconate dehydrogenase into ribulose-5-phosphate. In this step also NADP+ acts as the electron acceptor and produce NADPH.
Therefore,reactions B and F produces NADPH.
(c)
Interpretation:
Ribulose-5-phosphate should be identified.
Concept introduction:
Ribulose-5-phosphate is the productof pentose phosphate pathway.
Answer to Problem 28P
The compound G in the reaction is Ribulose-5-phosphate.
Explanation of Solution
As the first step of oxidative phase of pentose phosphate pathway, C-1 of glucose-6-phosphate is dehydrogenated into 6-phosphoglucono-⏹-lactone by glucose-6-phosphate dehydrogenase. Then this 6-phosphoglucono-⏹-lactone is hydrolyzed by a lactonase resulting 6-phosphogluconate. This 6 C sugar acid is then decarboxylated by 6-phosphogluconate dehydrogenase into ribulose-5-phosphate.
Therefore, Gis Ribulose-5-phosphate.
(d)
Interpretation:
The CO2generating reaction should be determined.
Concept introduction:
The decarboxylation reactions generate CO2 as a by-product.
Answer to Problem 28P
The reactions F produce CO2.
Explanation of Solution
The six C sugar acid, 6-phosphogluconate formed during pentose phosphate pathway is oxidatively decarboxylated by 6-phosphogluconate dehydrogenase into ribulose-5-phosphate. The final product is a five-carbon sugar, and release CO2.
So. the reaction F produce CO2.
(e)
Interpretation:
6-phosphogluconate should be identified.
Concept introduction:
6-phosphogluconate is a 6C sugar acid which forms during pentose phosphate pathway.
Answer to Problem 28P
The compound E in the reaction is 6-phosphogluconate.
Explanation of Solution
In the first step of the oxidative phase of pentose phosphate pathway, C-1 of glucose-6-phosphate is dehydrogenated into 6-phosphoglucono-⏹-lactone by glucose-6-phosphate dehydrogenase which is hydrolyzed by a lactonase resulting 6-phosphogluconate.
The end product of above reaction is 6-phosphogluconate. Thus the compound E in the reaction is 6-phosphogluconate.
(f)
Interpretation:
The reaction that is catalyzed by phosphopentose isomerase should be determined.
Concept introduction:
Phosphopentose isomerase is an enzyme which involves in isomerization reaction.
Answer to Problem 28P
The reactions H uses Phosphopentose isomerase enzyme.
Explanation of Solution
Ribulose-5-phosphate is isomerized to ribose-5-phosphate by phosphopentose isomerase. The enzyme, phosphopentose isomerase catalyze the conversion of a ketose sugar (Ribulose-5-phosphate ) to an aldose sugar (ribose-5-phosphate).
Therefore, the reaction H needs the enzyme phosphopentose isomerase.
(g)
Interpretation:
Ribose-5-phosphate should be identified.
Concept introduction:
Ribose-5-phosphate is the end product of the oxidative phase of pentose phosphate pathway.
Answer to Problem 28P
The compound I in the reaction is Ribose-5-phosphate.
Explanation of Solution
The ribulose-5-phosphate is obtained in pentose phosphate pathway when the ribose-5-phosphate is isomerized by phosphopentose isomerase.
Therefore, the compound I in the reaction is Ribose-5-phosphate.
(h)
Interpretation:
Reaction catalyzed by lactonase should be determined.
Concept introduction:
Lactonases catalyzes the hydrolysis of ester bonds.
Answer to Problem 28P
The reactions D uses the enzymeLactonases.
Explanation of Solution
The degydrogenated product of glucose-6-phospahte is 6-phosphoglucono-⏹-lactone. This is a 6 membered ring structure and have an ester bond between C-1 carbonyl carbon and C-5 hydroxyl Oxygen. This bond is hydrolyzed by lactonase and to produce 6-phosphogluconate. The reaction is indicated by letter D.
(i)
Interpretation:
Glucose-6-phosphate should be identified.
Concept introduction:
The pentose phosphate pathway is initiated by the oxidation of glucose-6-phosphate.
Answer to Problem 28P
The compound A in the reaction is glucose-6-phosphate.
Explanation of Solution
Glucose-6-phosphate is a 6-carbon sugar and have a ring structure where the hydroxyl group at C-6 is phosphorylated.
The compound A in the reaction is glucose-6-phosphate.
(j)
Interpretation:
The reaction catalyzed by 6-phosphogluconate dehydrogenase should be determined.
Concept introduction:
Dehydrogenases are the enzymes which catalyzes the removal of hydrogen molecules with the help of coenzymes NAD and FAD.
Answer to Problem 28P
The reactions F uses the enzymedehydrogenases.
Explanation of Solution
6-phosphogluconate is oxidatively decarboxylated by 6-phosphogluconate dehydrogenase into ribulose-5-phosphate which is indicated by reaction F.
(k)
Interpretation:
Reaction that is catalyzed by glucose-6-phosphate dehydrogenase should be determined.
Concept introduction:
In the first reaction of pentose phosphate pathway glucose-6-phosphate is dehydrogenated to produce phosphoglucono-⏹-lactone.
Answer to Problem 28P
The reactions B uses the enzymeglucose-6-phosphate dehydrogenases.
Explanation of Solution
In the first step of pentose phosphate pathway, Glucose-6-phosphate is dehydrogenated at C-1 by glucose-6-phosphate dehydrogenase enzyme into 6-phosphoglucono-⏹-lactone.
So, the reactions B uses the enzymeglucose-6-phosphate dehydrogenases.
Want to see more full solutions like this?
Chapter 20 Solutions
BIOCHEMISTRY W/1 TERM ACHEIVE ACCESS
- Biochemistry Question Please help. Thank you What is the function of glutamate dehydrogenase?arrow_forwardBiochemistry Question Please help. Thank you How and why does a high protein diet affect the enzymes of the urea cycle?arrow_forwardBiochemistry What is the importance of the glucose-alanine cycle?arrow_forward
- Biochemistry Assuming 2.5 molecules of ATP per oxidation of NADH/(H+) and 1.5molecules of ATP per oxidation of FADH2, how many ATP are produced per molecule of pyruvate? Please help. Thank youarrow_forward1. How would you explain the term ‘good food’? 2. How would you define Nutrition? 3. Nutrients are generally categorised into two forms. Discuss.arrow_forwardBiochemistry Question. Please help solve. Thank you! Based upon knowledge of oxidation of bioorganic compounds and howmuch energy is released during their oxidation, rank the following, from most to least, with respect to how much energy would be produced from each during their oxidation. Explain your placement for each one.arrow_forward
- Biochemistry Question.For the metabolism of amino acids what is the first step for theirbreakdown? Why is it necessary for this breakdown product to be transported to the liver? For the catabolism of the carbon backbone of these amino acids, there are 7 entry points into the “standard” metabolic pathways. List these 7 entry points and which amino acids are metabolized to these entry points. Please help. Thank you!arrow_forwardBiochemistry Question. Please help. Thank you. You are studying pyruvate utilization in mammals for ATP production under aerobic conditions and have synthesized pyruvate with Carbon #1 labelled with radioactive C14. After only one complete cycle of the TCA cycle, which of the TCA cycle intermediates would be labeled with C14? Explain your answer. Interestingly, you find C14 being excreted in the urine. How does it get there?arrow_forwardBiochemistry question. Please help with. Thanks in advance For each of the enzymes listed below, explain what the enzyme does including function, names (or structures) of the substrate and products and the pathway(s) (if applicable) it is/are found in. (a) ATP synthetase (b) succinate dehydrogenase (c) isocitrate lyase (d) acetyl CoA carboxylase (e) isocitrate dehydrogenase (f) malate dehydrogenasearrow_forward
- Draw and name each alcohol and classify it as primary, secondary, or tertiary. Explain your answer thoroughly.arrow_forwardDraw the product of each reaction. If there are multiple products, draw only the major product. Explain your answer thoroughly.arrow_forwardIdentify the type of bond in the following disaccharides. Number your carbons to show work. Explain your answer thoroughly. Draw the number of carbons also.arrow_forward
BiochemistryBiochemistryISBN:9781319114671Author:Lubert Stryer, Jeremy M. Berg, John L. Tymoczko, Gregory J. Gatto Jr.Publisher:W. H. Freeman
Lehninger Principles of BiochemistryBiochemistryISBN:9781464126116Author:David L. Nelson, Michael M. CoxPublisher:W. H. Freeman
Fundamentals of Biochemistry: Life at the Molecul...BiochemistryISBN:9781118918401Author:Donald Voet, Judith G. Voet, Charlotte W. PrattPublisher:WILEY
BiochemistryBiochemistryISBN:9781305961135Author:Mary K. Campbell, Shawn O. Farrell, Owen M. McDougalPublisher:Cengage Learning
BiochemistryBiochemistryISBN:9781305577206Author:Reginald H. Garrett, Charles M. GrishamPublisher:Cengage Learning
Fundamentals of General, Organic, and Biological ...BiochemistryISBN:9780134015187Author:John E. McMurry, David S. Ballantine, Carl A. Hoeger, Virginia E. PetersonPublisher:PEARSON