Phosphocholine
Encyclopedia
- Not to be confused with phosphatidylcholinePhosphatidylcholinePhosphatidylcholines are a class of phospholipids that incorporate choline as a headgroup.They are a major component of biological membranes and can be easily obtained from a variety of readily available sources such as egg yolk or soy beans from which they are mechanically extracted or chemically...
.
Phosphocholine is an intermediate in the synthesis of phosphatidylcholine
Phosphatidylcholine
Phosphatidylcholines are a class of phospholipids that incorporate choline as a headgroup.They are a major component of biological membranes and can be easily obtained from a variety of readily available sources such as egg yolk or soy beans from which they are mechanically extracted or chemically...
in tissues. Phosphocholine is made in a reaction, catalyzed by choline kinase
Choline kinase
Choline Kinase is an enzyme which catalyzes the first reaction in the choline pathway for phosphatidylcholine biosynthesis.This reaction involves the transfer of a phosphate group from ATP to choline in order to form phosphocholine.Thus, the two substrates of this enzyme are ATP and choline,...
, that converts ATP + Choline into Phosphocholine and ADP. Phosphocholine is a molecule found for example in lecithin
Lecithin
Lecithin is a generic term to designate any group of yellow-brownish fatty substances occurring in animal and plant tissues, and in egg yolk, composed of phosphoric acid, choline, fatty acids, glycerol, glycolipids, triglycerides, and phospholipids .The word lecithin was originally coined in 1847 by...
.
It is also used by nematode
Nematode
The nematodes or roundworms are the most diverse phylum of pseudocoelomates, and one of the most diverse of all animals. Nematode species are very difficult to distinguish; over 28,000 have been described, of which over 16,000 are parasitic. It has been estimated that the total number of nematode...
s and human placenta
Placenta
The placenta is an organ that connects the developing fetus to the uterine wall to allow nutrient uptake, waste elimination, and gas exchange via the mother's blood supply. "True" placentas are a defining characteristic of eutherian or "placental" mammals, but are also found in some snakes and...
s as a posttranslational modification
Posttranslational modification
Posttranslational modification is the chemical modification of a protein after its translation. It is one of the later steps in protein biosynthesis, and thus gene expression, for many proteins....
to suppress an immune response by their hosts.
It is also one of the binding targets of C-reactive protein
C-reactive protein
C-reactive protein is a protein found in the blood, the levels of which rise in response to inflammation...
(CRP). Thus when a cell is damaged, CRP binds to phosphocholine beginning the recognition and phagocytotic immunologic response.
Phosphatidylcholine is one of the natural constituents of hens' eggs (and many other eggs), in the form of Egg-PC, which is often used in biomimetic membrane studies. It can be purchased in purified form from many sources. The PC group is usually divided into natural (like EggPC) and synthetic products.