cofactors

Catalytic diversity

The range of reactions that an enzyme can catalyze depends on the specific arrangement of amino acids in its active site.

Cofactors

Cofactors are essential components of the active site of cofactor-dependent enzymes and often participate in catalysis.

Catalysis

Catalysis refers to the process of increasing the rate of a chemical reaction with the help of a catalyst.

Apoenzymes

Apoenzymes are the inactive forms of enzymes that require a cofactor to be converted into holoenzymes, which are the active forms.

Essential ions

Essential ions are inorganic compounds, mostly metal ions, that act as cofactors in enzyme reactions. They can be classified into activator ions and metal ions of metalloenzymes.

Coenzymes

Coenzymes are organic compounds that act as group-transfer reagents and are specific for the chemical groups they accept and donate.

Cosubstrates

Cosubstrates are loosely bound coenzymes that serve as substrates in enzyme-catalyzed reactions.

Prosthetic groups

Prosthetic groups are tightly bound coenzymes that remain bound to the enzyme and must return to their original structure during each catalytic cycle.

Mobile metabolic groups

Mobile metabolic groups are attached to the reactive center of coenzymes and shuttle chemical groups among different enzyme-catalyzed reactions.

Minerals

Many minerals are essential cofactors for organisms and play important roles in enzyme reactions. Examples include Na+, Mg2+, K+, Ca2+, and Cl-.

Metalloenzymes

Metalloenzymes are enzymes that have firmly bound metal ions at their active sites. Examples include zinc, iron, copper, and cobalt.

Electrophilic catalysts

Metal ions in metalloenzymes act as electrophilic catalysts by attracting electrons and leading to bond polarization or destabilization.

Carbonic anhydrase

Carbonic anhydrase is a metalloenzyme that catalyzes the rapid interconversion of CO2 and H2O to carbonic acid, protons, and bicarbonate ions.

Glaucoma

Glaucoma is a disease that can occur due to the absence or malfunction of carbonic anhydrase, leading to an imbalance in fluid levels in the eye.

Iron-sulfur clusters

Iron-sulfur clusters are non-heme groups that contain iron and sulfur and are involved in reversible oxidation and reduction reactions.

Heme groups

Heme groups occur in catalase and cytochromes and are associated with metalloenzymes in mitochondria and chloroplasts.

Vitamins

Coenzymes are often derived from vitamin precursors, which undergo biochemical conversion to transform into their active coenzyme forms.

Water-soluble vitamins

Water-soluble vitamins, such as B-vitamins, are required daily in small amounts and are readily excreted via urine.

Fat-soluble vitamins

Fat-soluble vitamins, such as vitamins A, D, E, and K, are stored by animals in adipose tissues and can induce toxic conditions when excessively consumed (hypervitaminoses).