Organic Chemistry
7th Edition
ISBN: 9780321803221
Author: Paula Y. Bruice
Publisher: Prentice Hall
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Textbook Question
Chapter 24.5, Problem 17P
Explain why the ability of PLP to catalyze an amino acid transformation is greatly reduced if the OH substituent of pyridoxal phosphate is replaced by OCH3.
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Chapter 24 Solutions
Organic Chemistry
Ch. 24.1 - Prob. 2PCh. 24.1 - Prob. 3PCh. 24.2 - How many conjugated double bonds are there in a....Ch. 24.2 - Instead of adding to the 4a position and...Ch. 24.2 - Prob. 7PCh. 24.3 - Prob. 8PCh. 24.3 - Acetolactate synthase is another TPP-requiring...Ch. 24.3 - Acetolactate synthase transfers the acyl group of...Ch. 24.5 - Prob. 12PCh. 24.5 - The enzyme that catalyzes the C C bond cleavage...
Ch. 24.5 - Propose a mechanism for the ,-elimination reaction...Ch. 24.5 - Which compound is more easily decarboxylated?Ch. 24.5 - Explain why the ability of PLP to catalyze an...Ch. 24.5 - Explain why the ability of PLP to catalyze an...Ch. 24.6 - Ethanolamine ammonia lyase, a coenzyme...Ch. 24.6 - Prob. 19PCh. 24.7 - How do the structure of tetrahydrofolate and...Ch. 24.7 - What is the source of the methyl group in...Ch. 24.8 - Thiols such as ethanethiol and propanethiol can be...Ch. 24 - How does the metal ion in carboxypeptidase A...Ch. 24 - Prob. 23PCh. 24 - Prob. 24PCh. 24 - Prob. 25PCh. 24 - S-Adenosylmethionine (SAM) is formed from the...Ch. 24 - Prob. 27PCh. 24 - What acyl groups have we seen transferred by...Ch. 24 - Propose a mechanism for the following reaction:Ch. 24 - When transaminated, the three branched-chain amino...Ch. 24 - Draw the products of the following reaction, where...Ch. 24 - When UMP is dissolved in T2O, exchange of T for H...Ch. 24 - Dehydratase is a PLP-requiring enzyme that...Ch. 24 - In addition to the reaction mentioned in Section...Ch. 24 - PLP can catalyze both ,-elimination reactions...Ch. 24 - The glycine cleavage system is a group of four...Ch. 24 - Prob. 37PCh. 24 - FADH2 reduces , -unsaturated thioesters to...
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- 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_forwardOne of the steps in the pentose phosphate pathway for glucose catabolism is the reaction of xylulose 5-phosphate with ribose 5-phosphate in the presence of a transketolase to give glyceraldehyde 3-phosphate and sedoheptulose 7-phosphate. (a) The first part of the reaction is nucleophilic addition of thiamin diphosphate (TPP) ylide to xylulose 5-phosphate, followed by a retro-aldol cleavage to give glyceraldehyde 3-phosphate and a TPPcontaining enamine. Show the structure of the enamine and the mechanism by which it is formed. (b) The second part of the reaction is addition of the enamine to ribose 5-phosphate followed by loss of TPP ylide to give sedoheptulose 7-phosphate. Show the mechanism.arrow_forwardThe first step in the catabolism of most amino acids is the removal of the nitrogen atom by transfer to an a-keto acid, a reaction catalyzed by an enzyme called a transaminase. The a-keto acid acceptor is often a-ketoglutarate. Modify the structures in the product to show the products of the transamination of cysteine. Be sure to show functional groups with the charge and number of attached hydrogen atoms appropriate for pH 7.4. transaminase + O=C H₂N-CH + CH₂ CH₂ CH₂ SH Incorrect H₂N || CH | CH₂ | CH₂ I || O || n | CH₂ T SHarrow_forward
- How prepare g-C3N4 from urea in laboratory?arrow_forward(i) Write the product obtained when D-glucose reacts with HCN. (ii) What type of bonding stabilizes the α-helix structure of proteins? (iii) Write the name of the disease caused by the deficiency of vitamin B12arrow_forwardExplain why the ability of PLP to catalyze an amino acid transformation is greatly reduced if the OH substituent of pyridoxal phosphate is replaced by OCH3.arrow_forward
- Write down the reactions: D-Glucopyranose + CH3I →arrow_forwardDraw the product formed by the condensation of citrulline with aspartate catalyzed by argininosuccinate synthetase in the second step of the urea cycle. Use wedges and dashes to indicate the stereochemistry at asymmetric centers. Provide the structure in the protonation state found in physiological conditions. H₂N HN, O O H H3N Drawing Coola argininosuccinate synthetase ATP -OOC, H3N H 1110 AMP, PPi COO- Qarrow_forward1 Drag items from the column on the right to the left to match the pairs Tetrodotoxin Cholera Toxin Pertussis Toxin Beta-blockers BOTOX Blocks aceylcholine release Prevents G-alpha-i from binding GTP. G-alpha-i is unable to inhibit adenylyl cyclase. Results in increased cAMP (mostly in lung cells) Blocks a receptor that activated G-alpha-s, thus, prevents the activation of G-alpha-s. Results in decreased cAMP (mostly in heart cells) Blocks voltage gated sodium channels Prevents G-alpha-s from hydrolyzing GTP. G-alpha- s can't turn off. Results in massive increase of CAMP (mostly in intestinal cells)arrow_forward
- Acetolactate synthase is another TPP-requiring enzyme. It transfers the acyl group of pyruvate 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.arrow_forwardglycerol + fatty acids triacylglycerol + H₂O Which types of specificity does this enzyme show? stereochemical specificity absolute specificity relative specificityarrow_forwardPropose a mechanism for the TPP-dependent step in isoleucine biosynthesis. Draw the predicted product of this reaction.arrow_forward
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