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an element or principle, e.g., a coenzyme, with which another must unite in order to function.
1. Synonym(s): coenzyme
2. An atom or molecule essential for the action of a large molecule, for example, heme in hemoglobin, magnesium in chlorophyll. Solo metal ions are regarded as cofactors for proteins, but not as coenzymes.
1. One of two or more contributing factors.
2. A substance, such as a metallic ion or coenzyme, that must be associated with an enzyme for the enzyme to function.
1. Synonym(s): coenzyme.
2. An atom or molecule essential for the action of a large molecule; e.g., heme in hemoglobin, magnesium in chlorophyll.
cofactora substance that is essential for the catalytic activity of some enzymes, binding to the enzyme only during the reaction. Cofactors can be metallic ions, or nonprotein organic molecules (coenzymes) such as vitamins in the B-COMPLEX.
An atom or molecule essential for the action of a large molecule.