Final answer:
Thioesters in CoA-SH can be stabilized in physiological conditions due to their structural features, including the presence of a nearby nitrogen atom. This stabilization is critical for metabolic pathways, such as those involving acyl group transfers and the catabolism of fatty acids.
Step-by-step explanation:
The question pertains to the stability of thioesters in biological systems, particularly in relation to Coenzyme A (CoA-SH) and fatty acid metabolism. Yes, thioesters can be stabilized at physiological conditions by certain functional groups.
The stability of the thioester bond in CoA-SH in fatty acid metabolism is a result of the presence of a nearby nitrogen atom.
This nitrogen is part of the CoA structure, which plays a crucial role in stabilizing the thioester bond against hydrolysis and other reactions that might otherwise occur due to the high reactivity of the thiol group in cellular environments.
CoA-SH represents a unique class of molecules where the thiol group is highly active for acyl group transfer but is also protected from unwanted reactivity by its complex structure, including the proximity of nitrogen atoms and the adenylate moiety.
This protection is essential because of the central role of CoA-SH in many metabolic pathways, such as the catabolism of carbohydrates and the ß-oxidation pathway for fatty acid metabolism.
The thioester bond is involved in the transfer of acetyl groups, such as when pyruvate transfers its acetyl group to HS-CoA, and is essential for the activation of fatty acids for subsequent metabolic processes.