Thekey differencebetween coenzyme and cofactor is that thecoenzymes are organic molecules, whereas the cofactors can be either organic or inorganic molecules.
Enzymesare essential biological macromolecules. They are the biological催化剂, which increases the rate of biological reactions under very mild conditions. Moreover, enzymes areproteins; thus, when they are subjected to a high level of heat, salt concentrations, mechanical forces, organic solvents and concentrated acid or base solutions, they tend to denaturize. Sometimes, enzymes need the support of another molecule or an ion to have the specific function. Coenzymes and cofactors are such molecules.
Coenzymes are smaller organic molecules than the enzyme (which is a protein). They are mainly organic molecules, and many of them derive from vitamins. For instance, niacin produces the coenzymeNAD+that is responsible for oxidation reactions.
Without the cofactors, the enzyme activity will be lost. We can divide these molecules broadly into two groups as organic cofactors and inorganic cofactors. Inorganic ones mainly include metal ions. However, these metal ions are often needed in trace amounts. For instance, magnesium is essential for hexokinase, DNA polymerase and Glucose-6-phosphate enzymes while zinc is an essential metal ion for alcohol dehydrogenase, carbonic anhydrase and DNA polymerase function.
- By binding to the substrate as to orient it properly for reaction
- And, by electrostatically stabilizing or shielding negative charges
- By facilitating oxidation, reduction reaction through reversible changes in the metal ions’ oxidation state
Moreover, organic cofactors are mainly vitamins and other non-vitamin organic molecules like ATP, glutathione, heme, CTP, coenzyme B, etc. We can divide organic cofactors further into two groups as the coenzyme and the prosthetic group. Prosthetic groups bind tightly with the enzyme and participate in the enzyme catalysis reaction. During the reaction, the enzyme- prosthetic group complex may undergo structural changes, but they are coming to the original state when the reaction is over. FAD is a prosthetic group of succinate dehydrogenase enzyme, which reduces to FADH2in the process of converting succinate to fumarate.
A coenzyme is an organic non-protein compound that binds with an enzyme to catalyze a reaction while a cofactor is a substance (other than the substrate) whose presence is essential for the activity of an enzyme. Hence, Coenzymes are a type of cofactors. The key difference between coenzyme and cofactor is that the coenzymes are organic molecules, whereas the cofactors can be either organic or inorganic molecules.
The below infographic presents the difference between coenzyme and cofactor in tabular form.
概括– Coenzyme vs Cofactor
1. Helmenstine, Anne Marie, Ph.D. “Coenzyme Definition and Examples.” ThoughtCo, Oct. 22, 2018.Available here
2. J.H. Freeland-Graves, C. Bavik, in Encyclopedia of Food Sciences and Nutrition (Second Edition), 2003