Phosphotransferases are a category of enzymes (EC number

EC number

The Enzyme Commission number is a numerical classification scheme for enzymes, based on the chemical reactions they catalyze....

 2.7) that catalyze phosphorylation

Phosphorylation

Phosphorylation is the addition of a phosphate group to a protein or other organic molecule. Phosphorylation activates or deactivates many protein enzymes....

 reactions. The general form of the reactions they catalyze is:
A—P + B ⇔ B—P + A

Where P is a phosphate group and A and B are the donating and accepting molecules, respectively.

Classification of Phosphotransferases

Phosphotransferases are generally classified according to the acceptor molecule.

• EC 2.7.1 Phosphotransferases with an alcohol group as acceptor
• EC 2.7.2 Phosphotransferases with a carboxy group as acceptor
• EC 2.7.3 Phosphotransferases with a nitrogenous group as acceptor
• EC 2.7.4 Phosphotransferases with a phosphate
  Phosphate
  A phosphate, an inorganic chemical, is a salt of phosphoric acid. In organic chemistry, a phosphate, or organophosphate, is an ester of phosphoric acid. Organic phosphates are important in biochemistry and biogeochemistry or ecology. Inorganic phosphates are mined to obtain phosphorus for use in...
  
   group as acceptor
• EC 2.7.9 Phosphotransferases with paired acceptors. In these reactions, a single triphophate-nucleotide
  Nucleotide
  Nucleotides are molecules that, when joined together, make up the structural units of RNA and DNA. In addition, nucleotides participate in cellular signaling , and are incorporated into important cofactors of enzymatic reactions...
  
   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

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 . It is known as multicomponent system that always involves enzymes of the plasma membrane and those in the...

 (PTS) is a complex group translocation system present in many bacteria. The PTS transports sugars (such as glucose

Glucose

Glucose is a simple sugar and an important carbohydrate in biology. Cells use it as the primary source of energy and a metabolic intermediate...

, mannose

Mannose

Mannose is a sugar monomer of the aldohexose series of carbohydrates. Mannose is a C-2 epimer of glucose. It is not part of human metabolism, but is a component of microbial cell walls, and is therefore a target of the immune system and also of antibiotics....

, and mannitol

Mannitol

Mannitol is a white, crystalline organic compound with the formula . This polyol is used as an osmotic diuretic agent and a weak renal vasodilator...

) 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 (Glu-6P).
Due to the negative charge of the phosphate, this Glu-6P can no longer freely leave the cell. This is the first reaction of glycolysis

Glycolysis

Glycolysis is the metabolic pathway that converts glucose C6H12O6, into pyruvate, CH3COCOO− + H+...

, which degrades the sugar to pyruvate.