Organic Chemistry (8th Edition)
8th Edition
ISBN: 9780134042282
Author: Paula Yurkanis Bruice
Publisher: PEARSON
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Chapter 23.3, Problem 9P
Acetolactate synthase is another TPP-requiring enzyme. It transfers the acyl group to another molecule of pyruvate, forming acetolactate. This is the first step in the biosynthesis of the amino acids valine and leucine. Propose a mechanism for this reaction.
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Chapter 23 Solutions
Organic Chemistry (8th Edition)
Ch. 23.1 - Prob. 2PCh. 23.1 - Prob. 3PCh. 23.2 - How many conjugated double bonds are there in a....Ch. 23.2 - Instead of adding to the 4a position and...Ch. 23.2 - Prob. 7PCh. 23.3 - Prob. 8PCh. 23.3 - Acetolactate synthase is another TPP-requiring...Ch. 23.3 - Acetolactate synthase transfers the acyl group of...Ch. 23.3 - Prob. 12PCh. 23.5 - Which compound is more easily decarboxylated?
Ch. 23.5 - Prob. 14PCh. 23.5 - Explain why the ability of PLP to catalyze an...Ch. 23.5 - Explain why the ability of PLP to catalyze an...Ch. 23.5 - The enzyme that catalyzes the C C bond cleavage...Ch. 23.5 - Propose a mechanism for the ,-elimination reaction...Ch. 23.6 - Ethanolamine ammonia lyase, a coenzyme...Ch. 23.6 - Prob. 20PCh. 23.7 - How do the structure of tetrahydrofolate and...Ch. 23.7 - What is the source of the methyl group in...Ch. 23.8 - Thiols such as ethanethiol and propanethiol can be...Ch. 23 - How does the metal ion in carboxypeptidase A...Ch. 23 - Prob. 24PCh. 23 - Prob. 25PCh. 23 - For each of the following reactions, name both the...Ch. 23 - Prob. 27PCh. 23 - When transaminated, the three branched-chain amino...Ch. 23 - What acyl groups have we seen transferred by...Ch. 23 - Propose a mechanism for the following reaction:Ch. 23 - Draw the products of the following reaction, where...Ch. 23 - When UMP is dissolved in T2O, exchange of T for H...Ch. 23 - Dehydratase is a PLP-requiring enzyme that...Ch. 23 - In addition to the reaction mentioned in Section...Ch. 23 - PLP can catalyze both ,-elimination reactions...Ch. 23 - The glycine cleavage system is a group of four...Ch. 23 - Prob. 37PCh. 23 - FADH2 reduces , -unsaturated thioesters to...
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- UDP-galactose-4-epimerase converts UDP-galactose to UDP-glucose. The reaction requires NAD+ as a coenzyme. a. Propose a mechanism for the reaction. b. Why is the enzyme called an epimerase?arrow_forwardWhat type of reaction would a PLP-containing enzyme catalyze if the bond most perpendicular to PLP was a C-COO- bond? A、racemization B、transamination C、aldol cleavage D、decarboxylationarrow_forwardIn the pentose phosphate pathway for degrading sugars, ribulose 5-phosphate is converted to ribose 5-phosphate. Propose a mechanism for the isomerization.arrow_forward
- The given mechanism of transamination reaction is shown below, What is the role of the pyridinium group in Step D? 1. It acts as an electron-donating group (source) of electrons to enhance deprotonation of the amino acid by the enzyme. 2. It acts as an electron-withdrawing group (sink) to facilitate deprotonation of the amino acid. 3. It plays the role of a Lewis base to coordinate the amino acid. 4. Both 2 and 3 are true.arrow_forwardThe given mechanism of transamination reaction is shown below, To complete the shuffling of amino groups and carbonyls, the PMP must be converted back to PLP. How would you predict that this occurs? 1. A separate reaction oxidizes the amine group of PMP to an aldehyde. 2. A separate reaction hydrolyzes the amine of PMP to an aldehyde. 3. A different ketoacid reacts with the amine of PMP, and the entire sequence runs backward. 4. Either 2 or 3 could occur.arrow_forwardImidazoleglycerol‑phosphate dehydratase is an enzyme in the histine biosynthesis pathway. It catalyzes the E1 dehydration of D‑erthyro‑imidazole‑glycerol phosphate to imidazole acetol‑phosphate. This is a rare example of a biological E1 reaction, as most biological elimination reactions occur through E1cB instead. In this reaction, D‑erthyro‑imidazole‑glycerol phosphate is first protonated to form a good leaving group. Then, the leaving group is ejected to form the resonance‑stabilized carbocation shown. Draw curved arrows forming the most stable resonance structure to explain why this reaction goes through an E1 mechanism. Draw curved arrows to form the most stable resonance structure.arrow_forward
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