Essential Organic Chemistry (3rd Edition)
3rd Edition
ISBN: 9780321937711
Author: Paula Yurkanis Bruice
Publisher: PEARSON
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Textbook Question
Chapter 18.11, Problem 25P
Explain why the ability of PLP to catalyze an amino acid transformation is greatly reduced if a PLP requiring enzymatic reaction is carried out at a pH at which the pyridine nitrogen is not protonated.
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The 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
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transaminase
+
O=C
H₂N-CH
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CH₂
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H₂N
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CH
|
CH₂
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CH₂
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n
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CH₂
T
SH
Reaction of the a-carboxyl group of an amino acid or peptide with phenylisothiocyanate allows for the determination of the amino acid residue in the N-
terminus of an unknown peptide
O True
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Explain why the ability of PLP to catalyze an amino acid transformation is greatly reduced if a PLP-requiring enzymatic reaction is carried out at a pH at which the pyridine nitrogen is not protonated.
Chapter 18 Solutions
Essential Organic Chemistry (3rd Edition)
Ch. 18.1 - Prob. 1PCh. 18.2 - If H218O were used to hydrolyze lysozyme, which...Ch. 18.3 - Which of the following amino acid side chains can...Ch. 18.3 - Arginine and lysine side chains fit into trypsins...Ch. 18.4 - Which of the following amino acid side chains can...Ch. 18.4 - Prob. 6PCh. 18.5 - Prob. 7PCh. 18.5 - Draw the mechanism for the hydroxide-ion-catalyzed...Ch. 18.5 - What advantage does the enzyme gain by forming an...Ch. 18.7 - Prob. 10P
Ch. 18.7 - Prob. 11PCh. 18.8 - How many conjugated double bonds are there in a....Ch. 18.8 - Instead of adding to the 4a-position and...Ch. 18.8 - In succinate dehydrogenase, FAD is covalently...Ch. 18.8 - Prob. 15PCh. 18.9 - Acetolactate synthase is another TPP-requiring...Ch. 18.9 - Acetolactate synthase can also transfer the acyl...Ch. 18.9 - Prob. 18PCh. 18.9 - Prob. 19PCh. 18.10 - Prob. 21PCh. 18.11 - Prob. 23PCh. 18.11 - Which compound is more easily decarboxylated?Ch. 18.11 - Explain why the ability of PLP to catalyze an...Ch. 18.11 - Explain why the ability of PLP to catalyze an...Ch. 18.12 - What groups are interchanged in the following...Ch. 18.13 - Why is the coenzyme called tetrahydrofolate?Ch. 18.13 - What amino acid is formed by the following...Ch. 18.13 - How do the structures of tetrahydrofolate and...Ch. 18.13 - What is the source of the methyl group in...Ch. 18 - Prob. 32PCh. 18 - Prob. 33PCh. 18 - From what vitamins are the following coenzymes...Ch. 18 - Prob. 35PCh. 18 - For each of the following reaction, name both the...Ch. 18 - Explain why serine proteases do not catalyze...Ch. 18 - Prob. 38PCh. 18 - For each of the following enzyme catalyzed...Ch. 18 - Trisephosphate isomerase (TIM) catalyzes the...Ch. 18 - Prob. 41PCh. 18 - What acyl groups have we seen transferred by...Ch. 18 - When UMP is dissolved in T2O, exchange of T for H...Ch. 18 - Prob. 44PCh. 18 - When transaminated, the three branched-chain amino...Ch. 18 - Aldolase shows no activity if it is incubated with...
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