User:Alice Harmon/Sandbox 1
From Proteopedia
Eukaryotic Protein Kinase Catalytic Domain
Eukaryotic protein kinases are enzymes that transfer a phosphoryl group (-PO32-) from adenosine triphosphate (or more rarely from adenosine diphosphate) to the hydroxyl group of serine, threonine, or tyrosine residue of a protein substrate. Phosphorylation of the substrate can affect its activity and/or conformation and, in turn, the physiogy of the cell. Protein kinases act as switches that turn on or off metabolic and signaling pathways, and they play central roles in development, responses to the environment, and in diseases such as cancer. The number of protein kinase genes (and the percentage of the genome) for bakers yeast [1], humans [2] and rice [3] are 113 (2%),518 (2%), and 1429 (5%), respectively. The catalytic domains of these enzymes occur alone or with other functional domains in a single polypetide chain. Protein kinases may be monomeric or multimeric or found in complexes with regulatory protiens.
This article describes the general structure of protein kinase domains. It is based on the analysis of the primary structure of protein kinases by Hanks, Quinn, and Hunter [4] in which the amino acid sequences of 65 protein kinases were aligned, and the revised analysis by Hanks and Hunter [5], and on the first three-dimensional structure of protein kinase to be published, that of PKA by Knighton et al. [6]
