Coenzymes and Cofactors


Coenzymes and cofactors are molecules or ions that are used by enzymes to help catalyse reactions. Coenzymes are typically organic molecules that contain functionalities not found in proteins, while cofactors are catalytically essential molecules or ions that are covalently bound to the enzyme.

Keywords: enzyme; catalysis; functional group; metallocofactors

Figure 1.

Mechanism of the serine proteases. Note the role of general acid–base catalysis in each step of the mechanism. Step 1, nucleophilic attack of the serine hydroxyl on the substrate. Step 2, collapse of tetrahedral intermediate to the acyl enzyme intermediate. Step 3, release of amine product. Step 4, deacylation resulting from nucleophilic attack of water to form a tetrahedral intermediate. Step 5, collapse of the tetrahedral intermediate and release of carboxyl product.



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Further Reading

Bertini I, Gray HB, Lippard SJ and Valentine JS (1994) Bioinorganic Chemistry. Sausalito, CA: University Science Books.

Fersht A (1999) Structure and Mechanism in Protein Science. New York: W.H. Freeman & Co.

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Reedijk J (1993) Bioinorganic Catalysis. New York: Marcel Dekker.

Sigel H and Sigel A (1994) Metalloenzymes Involving Amino Acid‐Residue and Related Radicals. New York: Marcel Dekker.

Walsh CT (1979) Enzymatic Reaction Mechanisms. San Fransisco: W.H. Freeman & Co.

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Broderick, Joan B(Apr 2001) Coenzymes and Cofactors. In: eLS. John Wiley & Sons Ltd, Chichester. [doi: 10.1038/npg.els.0000631]