Enzymes, Coenzymes and Metabolic Pathways

Enzymes are proteins that have been folded into complex structures and are found throughout the body. Enzymes are responsible for the chemical reactions that keep us alive - our metabolism. Enzymes catalyze (speed up) chemical reactions; in some situations, enzymes can make a chemical reaction millions of times faster than it would be otherwise. Enzymes are comparable to catalysts in that they have the chemical ability to speed up reactions without changing or consuming themselves. Carboxyl group transfer, peptide linkage hydrolysis, carbon bond breaking, and the conversion of compounds to their optical isomers are examples of biological reactions.

The presence of non-protein molecules termed coenzymes is critical for enzyme catalytic function. Because cofactors are tightly attached to apoenzymes, it is impossible to separate coenzymes from apoenzymes without denaturing the enzyme proteins. Coenzymes are usually vitamins or vitamin derivatives. They can sometimes operate as catalysts in the absence of enzymes, although not as successfully as when used in combination with enzymes.

A metabolic pathway is a linked series of chemical reactions that occur within a cell in biochemistry. Metabolites are the reactants, products, and intermediates of an enzymatic reaction that are altered by a series of chemical reactions catalyzed by enzymes.

• Immobilized enzyme
• Apoenzyme
• Holoenzyme
• Chemical engineering and enzyme