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 nucleoside-triphosphate diphosphatase () 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 ...

:a nucleoside triphosphate + H₂O

\rightleftharpoons

a nucleotide + diphosphate Thus, the two substrates of this enzyme are

nucleoside triphosphate A nucleoside triphosphate is a nucleoside containing a nitrogenous base bound to a 5-carbon sugar (either ribose or deoxyribose), with three phosphate groups bound to the sugar. They are the molecular precursors of both DNA and RNA, which are cha ...

and H₂O, whereas its two products are

nucleotide Nucleotides are organic molecules consisting of a nucleoside and a phosphate. They serve as monomeric units of the nucleic acid polymers – deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), both of which are essential biomolecules wi ...

and diphosphate. This enzyme belongs to the family of hydrolases, specifically those acting on acid anhydrides in phosphorus-containing anhydrides. The systematic name of this enzyme class is nucleoside-triphosphate diphosphohydrolase. This enzyme is also called nucleoside-triphosphate pyrophosphatase. This enzyme participates in

purine metabolism Purine metabolism refers to the metabolic pathways to synthesize and break down purines that are present in many organisms. Biosynthesis Purines are biologically synthesized as nucleotides and in particular as ribotides, i.e. bases attached to ri ...

and

pyrimidine metabolism Pyrimidine biosynthesis occurs both in the body and through organic synthesis. ''De novo'' biosynthesis of pyrimidine ''De Novo'' biosynthesis of a pyrimidine is catalyzed by three gene products CAD, DHODH and UMPS. The first three enzymes of ...

. For example, enzyme deoxyribonucleoside triphosphate pyrophosphatase, encoded by YJR069C in ''

S. cerevisiae ''Saccharomyces cerevisiae'' () (brewer's yeast or baker's yeast) is a species of yeast (single-celled fungus microorganisms). The species has been instrumental in winemaking, baking, and brewing since ancient times. It is believed to have bee ...

'' and exhibiting (d)ITPase and (d)XTPase activities, hydrolyses ITP, dITP, XTP and dXTP releasing pyrophosphate and

IMP IMP or imp may refer to: * Imp, a fantasy creature Arts and entertainment Fictional characters * Imp (She-Ra), a character in ''She-Ra: Princess of Power'' * Imp a character in '' Artemis Fowl: The Lost Colony'' * Imp, a character in the '' Clan ...

, dIMP, XMP and dXMP, respectively.

Structural studies

As of late 2007, 5 structures have been solved for this class of enzymes, with PDB accession codes , , , , and .

References

* EC 3.6.1 Enzymes of known structure {{3.6-enzyme-stub