Coenzyme

It is a cofactor, which is an organic compound directly involved in enzymatic catalysis (see Cofactor). Depending on the function performed, 3 classes of coenzymes are distinguished: 1) oxidation-reduction coenzymes (NAD⁺, NADP⁺, FMN, FAD, CoQ, ascorbic acid, glutathione) transfer electrons or hydrogen from the oxidizing substrate and deliver them to the reducing agent, e.g., oxygen; 2) coenzymes involved in bisubstrate reactions (CoA, pyridoxal phosphate, TDP, biotin, tetrahydrofolate, and methylcobalamin); 3) coenzymes necessary for isomerization and other specific processes, e.g., 5′-deoxyadenosylcobalamin. Based on origin and structural characteristics, 2 classes are distinguished: 1) vitamin coenzymes (thiamine, FAD, FMN, CoA, NAD⁺, NADP⁺, pyridoxal phosphate, tetrahydrofolate, biotin, ascorbate); 2) non-vitamin coenzymes (nucleotides, monosaccharide phosphates, metalloporphyrins, glutathione, CoQ).

Source | Glossary of Most Commonly Used Biomedical Terms and Concepts | Lithuanian University of Health Sciences | Academician Professor Antanas Praškevičius, Professor Laima Ivanovienė