enzymology Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. A ...

, a protein-histidine tele-kinase () is an

enzyme Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. A ...

that

catalyzes Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recyc ...

the

chemical reaction A chemical reaction is a process that leads to the IUPAC nomenclature for organic transformations, chemical transformation of one set of chemical substances to another. Classically, chemical reactions encompass changes that only involve the pos ...

:ATP + protein L-histidine

\rightleftharpoons

ADP + protein ''N^τ''-phospho-L-histidine Thus, the two substrates of this enzyme are

ATP ATP may refer to: Companies and organizations * Association of Tennis Professionals, men's professional tennis governing body * American Technical Publishers, employee-owned publishing company * ', a Danish pension * Armenia Tree Project, non ...

and protein L-histidine, whereas its two products are

ADP Adp or ADP may refer to: Aviation * Aéroports de Paris, airport authority for the Parisian region in France * Aeropuertos del Perú, airport operator for airports in northern Peru * SLAF Anuradhapura, an airport in Sri Lanka * Ampara Air ...

and protein Ntau-phospho-L-histidine. This enzyme belongs to the family of

transferase A transferase is any one of a class of enzymes that catalyse the transfer of specific functional groups (e.g. a methyl or glycosyl group) from one molecule (called the donor) to another (called the acceptor). They are involved in hundreds of di ...

s, specifically those transferring a phosphate group to the sidechain of

histidine Histidine (symbol His or H) is an essential amino acid that is used in the biosynthesis of proteins. It contains an α-amino group (which is in the protonated –NH3+ form under biological conditions), a carboxylic acid group (which is in the de ...

residues in

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respo ...

s (protein-histidine kinases). The systematic name of this enzyme class is ''ATP:protein-L-histidine Ntau-phosphotransferase''. Other names in common use include ''ATP:protein-L-histidine N-tele-phosphotransferase'', ''histidine kinase'', ''histidine protein kinase'', ''protein histidine kinase'', ''protein kinase (histidine)'', and ''HK3''.

References

* * EC 2.7.13 Enzymes of unknown structure {{2.7-enzyme-stub