Phosphotransferases are a category of
enzymes (
EC number 2.7) that catalyze
phosphorylation reactions. The general form of the reactions they catalyze is:
:A-P + B
B-P + A
Where ''P'' is a
phosphate group
In chemistry, a phosphate is an anion, salt, functional group or ester derived from a phosphoric acid. It most commonly means orthophosphate, a derivative of orthophosphoric acid .
The phosphate or orthophosphate ion is derived from phosph ...
and A and B are the donating and accepting molecules, respectively.
Classification
Phosphotransferases are generally classified according to the acceptor molecule.
, Classification in this article follows the rules of Enzyme Nomenclature of the Nomenclature Committee of the International Union of Biochemistry and Molecular Biology (NC-IUBMB).
*EC 2.7.1 Phosphotransferases with an alcohol group
In chemistry, a hydroxy or hydroxyl group is a functional group with the chemical formula and composed of one oxygen atom Chemical bond, covalently bonded to one hydrogen atom. In organic chemistry, alcohols and carboxylic acids contain one or ...
as acceptor
*EC 2.7.2 Phosphotransferases with a carboxy
In organic chemistry, a carboxylic acid is an organic acid that contains a carboxyl group () attached to an R-group. The general formula of a carboxylic acid is or , with R referring to the alkyl, alkenyl, aryl, or other group. Carboxylic ...
group as acceptor
*EC 2.7.3 Phosphotransferases with a nitrogenous group as acceptor
*EC 2.7.4 Phosphotransferases with a phosphate
In chemistry, a phosphate is an anion, salt, functional group or ester derived from a phosphoric acid. It most commonly means orthophosphate, a derivative of orthophosphoric acid .
The phosphate or orthophosphate ion is derived from phosph ...
group as acceptor
*EC 2.7.9 Phosphotransferases with paired acceptors. In these reactions, a single triphosphate-nucleotide transfers two phosphates to two different acceptor molecules, resulting in a monophosphate-nucleotide and two phosphorylated products.
Phosphotransferase system
The phosphotransferase system PEP group translocation, also known as the phosphotransferase system or PTS, is a distinct method used by bacteria for sugar uptake where the source of energy is from phosphoenolpyruvate (PEP). It is known to be a multicomponent system that always i ...
(PTS) is a complex group translocation system present in many bacteria. The PTS transports sugars (such as glucose
Glucose is a simple sugar with the molecular formula . Glucose is overall the most abundant monosaccharide, a subcategory of carbohydrates. Glucose is mainly made by plants and most algae during photosynthesis from water and carbon dioxide, u ...
, mannose
Mannose is a sugar monomer of the aldohexose series of carbohydrates. It is a C-2 epimer of glucose. Mannose is important in human metabolism, especially in the glycosylation of certain proteins. Several congenital disorders of glycosylation ...
, and mannitol
Mannitol is a type of sugar alcohol used as a sweetener and medication. It is used as a low calorie sweetener as it is poorly absorbed by the intestines. As a medication, it is used to decrease pressure in the eyes, as in glaucoma, and to lo ...
) into the cell. The first step of this reaction is phosphorylation of the substrate via phosphotransferase during transport. In the case of glucose, the product of this phosphorylation is glucose-6-phosphate (Glc-6P).
Due to the negative charge of the phosphate, this Glc-6P can no longer freely leave the cell. This is the first reaction of glycolysis, which degrades the sugar to pyruvate.
See also
* Kinase
* Phosphorylase
In biochemistry, phosphorylases are enzymes that catalyze the addition of a phosphate group from an inorganic phosphate (phosphate+hydrogen) to an acceptor.
:A-B + P A + P-B
They include allosteric enzymes that catalyze the production of gluco ...
* Diphosphotransferase
References
External links
*
{{Phosphotransferases
Transferases
EC 2.7