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O-phosphocholine
Phosphocholine is an intermediate in the synthesis of phosphatidylcholine in tissues. Phosphocholine is made in a reaction, catalyzed by choline kinase, that converts Adenosine triphosphate, ATP and choline into phosphocholine and Adenosine diphosphate, ADP. Phosphocholine is a molecule found, for example, in lecithin. In nematodes and human placentas, phosphocholine is selectively attached to other proteins as a posttranslational modification to suppress an immune response by their hosts. It is also one of the binding targets of C-reactive protein (CRP). Thus, when a cell is damaged, CRP binds to phosphocholine, beginning the recognition and phagocytotic immunologic response. Phosphocholine is a natural constituent of hens' eggs (and many other eggs) often used in biomimetic membrane studies. See also * Alkylphosphocholines * Choline * Phosphoethanolamine References External linksPhosphocholine 3D Structure Viewer {{PAF signaling Post-translational modificat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Choline Kinase Choline kinase (also known as CK, ChoK and choline phosphokinase) is an enzyme which catalyzes the first reaction in the choline pathway for phosphatidylcholine (PC) biosynthesis. This reaction involves the transfer of a phosphate group from adenosine triphosphate (ATP) to choline in order to form phosphocholine. :ATP + choline \rightleftharpoons ADP + O-phosphocholine Thus, the two substrates of this enzyme are ATP and choline, whereas its two products are adenosine diphosphate (ADP) and O-phosphocholine. Choline kinase requires magnesium ions (+2) as a cofactor for this reaction. This enzyme belongs to the family of transferases, specifically those transferring phosphorus-containing groups (phosphotransferases) with an alcohol group as acceptor. The first detailed investigation of the enzyme was conducted by McCamen in 1962, where it was shown that the brain is the richest source of the enzyme in mammalian tissue. A related enzyme, ethanolamine kinase, tends to co-purify ... < |