Organic Chemistry
7th Edition
ISBN: 9780321803221
Author: Paula Y. Bruice
Publisher: Prentice Hall
expand_more
expand_more
format_list_bulleted
Concept explainers
Videos
Textbook Question
Chapter 25, Problem 64P
A student is trying to determine the mechanism for a reaction that uses ATP to activate a carboxylate ion, which then reacts with a thiol. If the carboxylate ion attacks the γ-phosphorous of ATP, the reaction products are the thioester, ADP, and phosphate. However, whether it attacks the α-phosphorus or the β-phosphorus of ATP cannot be determined from the reaction products because the thioester, AMP, and pyrophosphate would be the products in both reactions. The mechanisms can be distinguished by a labeling experiment in which the enzyme, the carboxylate ion, ATP, and radioactively labeled pyrophosphate are incubated and then the ATP is isolated. If the isolated ATP is radioactive, attack occurred on the α-phosphorous. If it is not radioactive, then attack occurred on the β-phosphorous. Explain these conclusions.
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solution
Students have asked these similar questions
When are the α and β forms not interconvertible?
TPP is a coenzyme for transketolase, the enzyme that catalyzes the conversion of a ketopentose (xylulose5-phosphate) and an aldopentose (ribose-5-phosphate) to an aldotriose (glyceraldehyde-3-phosphate) and a ketoheptose (sedoheptulose-7-phosphate). Notice that the total number of carbons in the reactants and products is the same (5 + 5 = 3 + 7). Propose a mechanism for this reaction.
Please draw by hand. Triosephosphate isomerase (TIM) catalyzes the conversion of dihydroxyacetone phosphate to glyceraldehyde-3-phosphate. The enzyme's catalytic groups are Glu 165 and His 95. In the first step of the reaction, these catalytic groups function as a base and an acid catalyst, respectively. Propose a mechanism for the reaction.
ОН
2-03Р0
ОН
dihydroxyacetone phosphate
triosephosphate isomerase
2-03РО.
H
glyceraldehyde-3-phosphate
FYI Glu is glutamic acid and his is histadine
Chapter 25 Solutions
Organic Chemistry
Ch. 25.6 - Prob. 2PCh. 25.6 - Prob. 3PCh. 25.6 - Why does the OH group add to the -carbon rather...Ch. 25.6 - Prob. 5PCh. 25.6 - How many molecules of NADH are formed from the...Ch. 25.7 - Prob. 7PCh. 25.7 - Prob. 8PCh. 25.7 - The oxidation of glyceraldehyde-3-phosphate to...Ch. 25.7 - Prob. 10PCh. 25.8 - Prob. 11P
Ch. 25.8 - Prob. 12PCh. 25.8 - Prob. 13PCh. 25.8 - Propose a mechanism for the reduction of...Ch. 25.9 - Prob. 15PCh. 25.9 - Prob. 16PCh. 25.10 - Acid-catalyzed dehydration reactions are normally...Ch. 25.10 - Prob. 18PCh. 25.10 - Prob. 19PCh. 25.10 - Acid-catalyzed dehydration reactions are normally...Ch. 25.10 - Prob. 21PCh. 25.10 - Prob. 22PCh. 25.11 - Prob. 23PCh. 25.12 - a. What is the name of the enzyme that converts...Ch. 25.15 - Prob. 25PCh. 25.16 - Prob. 26PCh. 25.16 - Prob. 27PCh. 25.17 - Propose mechanisms for the Claisen condensation...Ch. 25.17 - Prob. 29PCh. 25.17 - Propose a mechanism for the conversion of...Ch. 25.17 - Propose a mechanism for the biosynthesis of...Ch. 25.17 - Propose a mechanism for the conversion of the E...Ch. 25.17 - The fluoro-substitued geranyl pyrophosphate shown...Ch. 25.17 - Prob. 35PCh. 25.18 - Draw the individual 1,2-hydride and 1,2-methyl...Ch. 25 - Prob. 38PCh. 25 - Prob. 39PCh. 25 - Prob. 40PCh. 25 - Prob. 41PCh. 25 - Prob. 42PCh. 25 - Prob. 43PCh. 25 - Prob. 44PCh. 25 - Prob. 45PCh. 25 - Prob. 46PCh. 25 - Prob. 47PCh. 25 - Prob. 48PCh. 25 - Prob. 49PCh. 25 - Prob. 50PCh. 25 - Prob. 51PCh. 25 - Prob. 52PCh. 25 - Prob. 53PCh. 25 - Prob. 54PCh. 25 - Prob. 55PCh. 25 - Prob. 56PCh. 25 - Prob. 57PCh. 25 - Prob. 58PCh. 25 - Prob. 59PCh. 25 - Prob. 60PCh. 25 - Prob. 61PCh. 25 - Prob. 62PCh. 25 - UDP-galactose-4-epimerase converts UDP-galactose...Ch. 25 - A student is trying to determine the mechanism for...Ch. 25 - What would be the results of the experiment in...Ch. 25 - Prob. 66PCh. 25 - Propose a mechanism for the biosynthesis of...Ch. 25 - Eudesmol is a sesquiterpene found in eucalyptus....
Knowledge Booster
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, chemistry and related others by exploring similar questions and additional content below.Similar questions
- One of the steps in the pentose phosphate pathway for glucose catabolism is the reaction of sedoheptulose 7-phosphate with glyceraldehydes 3-phosphate in the presence of a transaldolase to yield erythrose 4-phosphate and fructose 6-phosphate. (a) The first part of the reaction is the formation of a protonated Schiff base of sedoheptulose 7-phosphate with a lysine residue in the enzyme followed by a retro-aldol cleavage to give an enamine plus erythrose 4-phosphate. Show the structure of the enamine and the mechanism by which it is formed. (b) The second part of the reaction is a nucleophilic addition of the enamine to glyceraldehyde 3-phosphate followed by hydrolysis of the Schiff base to give fructose 6-phosphate. Show the mechanism.arrow_forwardThe hydrolysis of pyrophosphate to orthophosphate drives biosynthetic reactions such as DNA synthesis. In Escherichia coli, a pyrophosphatase catalyzes this hydrolytic reaction. The pyrophosphatase has a mass of 120 kDa and consists of six identical subunits. A unit of activity for this enzyme, U, is the amount of enzyme that hydrolyzes 10 umol of pyrophosphate in 15 minutes. The purified enzyme has a Vnax of 2800 U per milligram of enzyme. When (S] >> KM, how many micromoles of substrate can 1 mg of enzyme hydrolyze per second? Vnax = umol -s. mg- If cach enzyme subunit has one active site, how many micromoles of active sites, or (E]r, are there in 1 mg of enzyme? (Er = umol - mg-arrow_forwardIn this section of the course, you have come across two drugs which inhibit dihydrofolate reductase. One of thes drugs is used as an antibacterial drug and the other is used in treatment of cancer. Why is it that each of these drugs can only be used for one purpose (and not the other) in clinical medicine.arrow_forward
- The same E1–E2–E3 multienzyme structure found in the pyruvate dehydrogenase and the a-ketoglutarate dehydrogenase complexes is also used in the branched-chain a-ketoacid dehydrogenase complex, which participates in the catabolism of branched-chain amino acids. Draw the reaction product when the following substrate is acted on by the branched-chain a-keto acid dehydrogenase complex.arrow_forwardThe correct expression for the autoprotolysis of CH3COOH is O2CH3COOH - CH3COOH +OH¯ O 2CH3COOH CH3COO CH3COOH2* O CH3COOH= CH3COO¯ + CH3COOH2* 2CH3COOH CH3COOH + CH3COOH2 2CH3COOH CH3COO¯ + HOOOSHarrow_forwardDraw the complete, step-wise mechanism of a phosphate transfer reaction that follows a concerted pathway or SN2 type reaction pathway. Clearly depict the transition state of the reaction.. R₁ B: ti R2 ertarrow_forward
- Human xanthine oxidase catalyzes the oxidation of hypoxanthine to xanthine and can further catalyze the oxidation of xanthine to uric acid. For the treatment of hyperuricemia and gout, several medications are used to inhibit the activity of xanthine oxidase and reduce the production of uric acid. You are a biochemist and just discovered a chemical that can inhibit the activity of the human xanthine oxidase. When analyzing its mode of inhibition, you found that the enzyme inhibitor complex requires 450 J/mol to dissociate and that it displays kinetics somehow similar to noncompetitive inhibition. You sent your inhibitor to the ministry of health for approval as a medication for gout. Based on the data provided, are they going to authorize it as a medication or not? Explain?arrow_forwardHuman xanthine oxidase catalyzes the oxidation of hypoxanthine to xanthine and can further catalyze the oxidation of xanthine to uric acid. For the treatment of hyperuricemia and gout, several medications are used to inhibit the activity of xanthine oxidase and reduce the production of uric acid. You are a biochemist and just discovered a chemical that can inhibit the activity of the human xanthine oxidase. When analyzing its mode of inhibition, you found that the enzyme inhibitor complex requires 450 kJ.mol to dissociate and that it displays kinetics somehow similar to noncompetitive inhibition. You sent your inhibitor to the ministry of health for approval as a medication for gout. Based on the data provided, are they going to authorize it as a medication or not? Explain?arrow_forwardExplain why the half-life (the time it takes for one-half of the compound to be metabolized) of Xylocaine is longer than that of Novocaine.arrow_forward
- Identify the most likely additional substrates, products, and coenzymes for each reaction in the following imaginary pathway.arrow_forwardThe correct expression for the autoprotolysis of CH3COOH is O 2CH3COOH = CH3COO" + CH3COOH2* 2CH3COOH = CH3COO" + CH3COOH 2CH3COOH = CH3COOH + CH3COOH2* 2CH3COOH = CH3COOH +OH CH3COOH = CH3COO" + CH3COOH2*arrow_forwardIn PLP-catalyzed reactions, the bond broken in the substrate molecule must be perpendicular to the plane of the pyridinium ring. Considering the bonds present in this ring, describe why this arrangement stabilizes the carbanion.arrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
Organic ChemistryChemistryISBN:9781305580350Author:William H. Brown, Brent L. Iverson, Eric Anslyn, Christopher S. FootePublisher:Cengage Learning
Organic Chemistry
Chemistry
ISBN:9781305580350
Author:William H. Brown, Brent L. Iverson, Eric Anslyn, Christopher S. Foote
Publisher:Cengage Learning
Enzymes - Effect of cofactors on enzyme; Author: Tutorials Point (India) Ltd;https://www.youtube.com/watch?v=AkAbIwxyUs4;License: Standard YouTube License, CC-BY
Enzyme Catalysis Part-I; Author: NPTEL-NOC IITM;https://www.youtube.com/watch?v=aZE740JWZuQ;License: Standard Youtube License