Question

What are the components that comprise Coenzyme A (Figure 1)?

A. β-Mercaptoethylamine, phosphopantothenate, dAMP with additional 3′-phosphate
B. β-Mercaptopropylamine, pantothenate, AMP with additional 5′-phosphate
C. β-Mercaptopropylamine, phosphopantothenate, dAMP with additional 5′-phosphate
D. β-Mercaptoethylamine, pantothenate, ADP with additional 3′-phosphate

Answer 1

Coenzyme A is comprised of β-mercaptoethylamine, pantothenate (vitamin B5), and ADP with an additional 3′-phosphate. Pantothenic acid is vital for its role in forming acetyl CoA, a central molecule in many metabolic processes.

Step-by-step explanation:

The components that comprise Coenzyme A (CoA) are essential for its biological function. CoA is made up of β-mercaptoethylamine, pantothenate (pantothenic acid), and ADP with an additional 3′-phosphate. Pantothenic acid, also known as vitamin B5, is a key component as it forms part of the structure of CoA and is involved in the activation of acetyl groups to form acetyl-CoA. This activated form is crucial for multiple metabolic pathways including fatty acid oxidation and the citric acid cycle.

The other components of CoA are derived from the adenine nucleotide, which includes adenine attached to a ribose sugar, and a pair of phosphate groups, collectively referred to as ADP. An additional phosphate is linked to the 3′ position of the ribose ring, which enhances the molecule's ability to participate in biochemical reactions, particularly the transfer of acetyl groups. The thiol group of β-mercaptoethylamine helps in the formation of thioester bonds, which are central to the molecule's function in acyl group transfers.