Question 1

In addition to TPP,which of the following coenzymes is/are required to facilitate the following reaction?

Accepted Answer

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Question 2

Give the products for the following reaction.

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Question 3

How does CoASH used in biological systems to activate carboxylic acids?

Accepted Answer

CoASH (coenzyme A) is involved in the activation of carboxylic acids by converting them into thioesters. This is an important step in many biological processes, including fatty acid metabolism and the citric acid cycle. Thioesters are more reactive than regular esters and can undergo various enzymatic reactions, such as transesterification, acylation, and nucleophilic substitution. This reaction is also known as the acyl-CoA synthetase reaction, which requires ATP hydrolysis to drive the formation of the thioester bond.

Question 4

Which of the following reactions of amino acids is not catalyzed by PLP-requiring enzymes?

Accepted Answer

PLP-requiring enzymes catalyze decarboxylation, transamination, and α,β-elimination reactions of amino acids. However, α-keto esterification is not catalyzed by PLP-requiring enzymes.

Question 5

What does the term "Pyridoxal" stand for?

Accepted Answer

The term "pyridoxal" stands for pyridine aldehyde, which consists of a pyridine ring with an aldehyde functional group (-CHO) attached to it.

Question 6

Give the purpose of TPP as a coenzyme.

Accepted Answer

TPP (thiamine pyrophosphate) functions as a coenzyme that catalyzes the transfer of a two-carbon fragment, specifically in the decarboxylation of pyruvate in the Krebs cycle and in the transketolase reaction during the pentose phosphate pathway.

Question 7

What is the first reaction in the catabolism of most amino acids?

Accepted Answer

The first reaction in the catabolism of most amino acids is transamination, which involves the transfer of an amino group from the amino acid to an alpha-keto acid, resulting in the formation of a new amino acid and a new alpha-keto acid. This reaction is catalyzed by aminotransferases, also known as transaminases. Decarboxylation, phosphorylation, aldolation, and ligation are not typically involved in the first step of amino acid catabolism.

Question 8

Which of the following is the sequence of steps followed by biotin-dependent enzymes,as listed below? I.Transfer of the carboxyl group from carboxybiotin to the substrate
II)Activation of bicarbonate by ATP
III)Formation of carboxybiotin

Accepted Answer

The correct sequence for biotin-dependent enzymes is: Activation of bicarbonate by ATP, formation of carboxybiotin, and then transfer of the carboxyl group from carboxybiotin to the substrate.

Question 9

Propose a mechanism for the following reaction.

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Question 10

Show the transimination (trans-Schiffization)reaction that happens in all PLP-requiring enzymes in which the amino acid substrate forms a Schiff base with PLP,thereby freeing the lysine side chain.

Accepted Answer

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Question 11

Give the purpose of biotin.

Accepted Answer

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Question 12

Which of the following reactions does the coenzyme biotin catalyze?

Accepted Answer

Biotin functions as a coenzyme in carboxylation reactions, where it facilitates the addition of a carboxyl group (-COOH) to substrates. Specifically, it is involved in the carboxylation of a carbon atom adjacent to an ester or keto group, making option E correct.

Question 13

Which of the following are required species for biotin-dependent enzymes?

Accepted Answer

Biotin-dependent enzymes require ATP for the activation of the carboxylase enzyme, Mg2+ as a cofactor, and bicarbonate (HCO3-) as a source of the CO2 group that is added to the substrate. Therefore, all listed species (A, B, and C) are required for the function of biotin-dependent enzymes.

Question 14

Which of the following coenzymes is required for the enzyme catalyzed reaction shown below? Xylose-5-P + Ribose-5-P  Glyceraldehyde-3-P + Sedoheptulose-7-P

Accepted Answer

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Question 15

Identify the compound below.

Accepted Answer

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...

Question 16

Give the product for the following reaction.

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Question 17

What metal ion is also required by biotin-dependent enzymes?

Accepted Answer

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Question 18

Which of the following reactions is called an α,β-elimination of an amino acid?

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Question 19

Which of the following statements best describes what an "electron sink" is?

Accepted Answer

An electron sink is a site for electron delocalization, often used in organic chemistry to stabilize negative charges by spreading them over a larger area.

Question 20

Give the product for the following reaction.

Accepted Answer

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Quiz 23: The Organic Chemistry of the Coenzymes, compounds Derived From Vitamins

In addition to TPP,which of the following coenzymes is/are required to facilitate the following reaction?

Give the products for the following reaction.

How does CoASH used in biological systems to activate carboxylic acids?

Which of the following reactions of amino acids is not catalyzed by PLP-requiring enzymes?

What does the term "Pyridoxal" stand for?

Give the purpose of TPP as a coenzyme.

What is the first reaction in the catabolism of most amino acids?

Which of the following is the sequence of steps followed by biotin-dependent enzymes,as listed below? I.Transfer of the carboxyl group from carboxybiotin to the substrate II) Activation of bicarbonate by ATP III) Formation of carboxybiotin

Propose a mechanism for the following reaction.

Show the transimination (trans-Schiffization)reaction that happens in all PLP-requiring enzymes in which the amino acid substrate forms a Schiff base with PLP,thereby freeing the lysine side chain.

Give the purpose of biotin.

Which of the following reactions does the coenzyme biotin catalyze?

Which of the following are required species for biotin-dependent enzymes?

Which of the following coenzymes is required for the enzyme catalyzed reaction shown below? Xylose-5-P + Ribose-5-P Glyceraldehyde-3-P + Sedoheptulose-7-P

Identify the compound below.

Give the product for the following reaction.

What metal ion is also required by biotin-dependent enzymes?

Which of the following reactions is called an α,β-elimination of an amino acid?

Which of the following statements best describes what an "electron sink" is?

Give the product for the following reaction.