How do vitamins support enzyme-controlled chemical reactions?

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Diagram showing how epinephrine binding to a beta-adrenergic receptor on a cell membrane activates a G-protein, which then stimulates adenylyl cyclase to convert ATP into cyclic AMP (cAMP), leading to physiological effects such as increased heart rate, blood vessel dilation, and glycogen breakdown. — Biochemistry In biochemistry, researchers study the chemical substances and processes that occur in living organisms and cells. In particular, various processes by which cells gain energy, such as epinephrine-stimulated cAMP synthesis, have been deduced through the study of biochemistry.

Vitamins, particularly those in the B-complex group, serve as essential components of enzyme systems by acting as coenzymes. In this capacity, they facilitate critical chemical reactions that allow the body to synthesize structural compounds and manage energy metabolism.1

These coenzymes support enzyme-controlled reactions through several key mechanisms:

Group Transfer: B-vitamin coenzymes transfer specific chemical groups between molecules, enabling the formation and utilization of proteins, fats, and carbohydrates.1
Metabolic Regulation: Coenzymes like coenzyme A—derived from pantothenic acid—act at the center of the tricarboxylic acid cycle, controlling the interconversion of nutrients into metabolic energy.1
Electron and Ion Transfer: Niacin and riboflavin coenzymes facilitate the movement of electrons and hydrogen ions, which is vital for the energy-producing reactions within the citric acid cycle.1

While vitamin C also participates in enzyme-catalyzed reactions, it functions primarily as a strong reducing agent by donating electrons to other molecules rather than acting as a traditional coenzyme.1