Coenzyme

A small organic molecule that binds to an enzyme and helps it catalyze a chemical reaction, often by carrying electrons or chemical groups between reactions.

Nicotinamide adenine dinucleotide: A coenzyme that carries electrons between oxidation–reduction reactions in cells. Its NAD⁺ and NADH forms illustrate how coenzymes shuttle electrons.
Enzyme: A biological catalyst, usually a protein, that accelerates chemical reactions without being consumed. A coenzyme assists an enzyme but does not usually catalyze the reaction alone.
Vitamin: An organic nutrient needed in small amounts for normal growth and metabolism. Several vitamins supply the molecular precursors from which coenzymes are made.
Glycolysis: A metabolic pathway that converts glucose into pyruvate while producing ATP and NADH. NAD⁺ accepts electrons during a key oxidation step in the pathway.
Metal ion: An electrically charged metal atom that can serve as an enzyme cofactor. Metal ions are inorganic cofactors, unlike organic coenzymes.
Flavin adenine dinucleotide: A coenzyme that accepts and donates electrons in oxidation–reduction reactions. Its tightly bound flavin group transfers electrons within many enzyme reactions.
Cofactor: A nonprotein component required for an enzyme's activity, including metal ions and organic molecules. Coenzymes are the organic subset of the broader cofactor category.
Vitamin B1: A water-soluble vitamin required for metabolism, also called thiamine. Cells convert thiamine into the coenzyme thiamine pyrophosphate.
Citric acid cycle: A sequence of reactions that oxidizes acetyl groups and generates reduced coenzymes. NAD⁺, FAD, and coenzyme A participate in its linked reactions.
Metal-binding enzyme: An enzyme whose activity depends on one or more bound metal ions. These enzymes show how catalysis can depend on an inorganic cofactor instead.

Linked from 8 pages