protein kinase An enzyme that catalyses the transfer of a phosphate group from ATP to an intracellular protein, thereby affecting the biological activity of the protein (see kinase). Protein kinases phosphorylate specific amino-acid residues of their target proteins, usually either serine, threonine, or tyrosine. They play an important role in increasing or decreasing enzyme activity and in transmitting signals from receptors on the cell surface (see signal transduction). The activity of the protein kinases is itself controlled by cyclic AMP, calcium ions, or other intracellular chemicals. It can be reversed by the action of phosphatase enzymes in the cell.
More From encyclopedia.com
Membrane , All living creatures are made of cells. One cellular component, the membrane, plays a crucial role in almost all cellular activities. The primary fun… Glycoproteins , Glycoproteins are proteins that contain covalently attached sugar residues. The hydrophilic and polar characteristics of sugars may dramatically chan… Lysosome , Lysosomes are membrane-bound organelles that function as the "stomachs" of eukaryotic cells . They contain about fifty different enzymes that break d… Protein Targeting , Protein Targeting Protein targeting refers to the methods cells use to get proteins to the proper location after synthesis. Proteins play a major rol… Retinol , Retinol Retinol, or vitamin A, is a necessary nutrient in all higher animals. It plays an important role in vision, in the maintenance of epithelial… Signal Transduction , To survive, an organism must constantly adjust its internal state to changes in the environment. To track environmental changes, the organism must re…
About this article
Updated About encyclopedia.com content Print Article
You Might Also Like