What is the role of cofactors and coenzymes in enzyme function?

Cofactors and coenzymes are essential for enzyme function, aiding in catalysis and regulation.

Cofactors are inorganic ions or molecules that bind to enzymes and assist in catalysis. They can act as electron carriers, transfer functional groups, or stabilize enzyme-substrate complexes. For example, zinc ions are cofactors for the enzyme carbonic anhydrase, which catalyses the conversion of carbon dioxide to bicarbonate ions in red blood cells.

Coenzymes are organic molecules that bind to enzymes and aid in catalysis by transferring chemical groups between molecules. They are often derived from vitamins and are essential for many metabolic pathways. For example, NAD+ is a coenzyme that accepts electrons and hydrogen ions during cellular respiration, allowing for the production of ATP.

In addition to aiding in catalysis, cofactors and coenzymes can also regulate enzyme activity. For example, ATP acts as an allosteric regulator for the enzyme phosphofructokinase, which is involved in glycolysis. When ATP levels are high, it binds to the enzyme and inhibits its activity, preventing the unnecessary breakdown of glucose.

Overall, cofactors and coenzymes play a crucial role in enzyme function, aiding in catalysis and regulation. Without them, many metabolic pathways would not be possible.