Protein, Conjugated

a protein that is composed of a simple protein and a nonprotein component, or a prosthetic group.

According to the nature of the prosthetic group, conjugated proteins are divided into glycoproteins, lipoproteins, nucleo-proteins, chromoproteins, and phosphoproteins. Many enzymes are also conjugated proteins. The prosthetic group is joined to the simple protein molecule by covalent or noncova-lent bonds; detachment of the prosthetic group results in a reduction of the stability of the protein component, or in its labili-zation. In some cases, denaturation of the protein component can occur.

Conjugated proteins are important to the vital activities of organisms. They participate in many key reactions during metabolism and energy transfer and serve as structural components of cells and tissues.