Nucleotidase
Encyclopedia
A nucleotidase is a hydrolytic enzyme
that catalyzes the hydrolysis
of a nucleotide
into a nucleoside
and a phosphate
. For example, they convert adenosine monophosphate to adenosine, and guanosine monophosphate
to guanosine
.
They have an important function in digestion
in that they break down consumed nucleic acids.
They can be divided into two categories, based upon the end which is hydrolyzed:
5' nucleotidases cleave off the phosphate from the 5' end of the sugar moiety. They can be classified into various kinds depending on their substrate preferences and subcellular localization. Membrane bound 5' nucleotidases displays specificity towards adenosine monophosphates and are predominantly involved in the salvage of preformed nucleotides and in signal transduction cascades involving purinergic receptors. Soluble 5' nucleotidases are all known to belong to the haloacid dehalogenase superfamily of enzymes which are two domian proteins characterised by a modified Rossman fold as the core and variable cap or hood. The soluble forms are further subclassified based on the criterion mentioned above. mdN and cdN are mitochondrial and cytosolic 5'-3' pyrimidine nucleotidases. cN-I is a cytosolic nucleotidase(cN) characterized by its affinity towards AMP as its substrate.cN-II is identified by its affinity towards either IMP or GMP or both. cN-III is a pyrimidine 5' nucleotidase. 5' nucleotidases are involved in varied functions like cell-cell communication, nucleic acid repair, purine salvage pathway for the synthesis of nucleotides, signal transduction, membrane transport etc.
Hydrolase
In biochemistry, a hydrolase is an enzyme that catalyzes the hydrolysis of a chemical bond. For example, an enzyme that catalyzed the following reaction is a hydrolase:-Nomenclature:...
that catalyzes the hydrolysis
Hydrolysis
Hydrolysis is a chemical reaction during which molecules of water are split into hydrogen cations and hydroxide anions in the process of a chemical mechanism. It is the type of reaction that is used to break down certain polymers, especially those made by condensation polymerization...
of a 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...
into a nucleoside
Nucleoside
Nucleosides are glycosylamines consisting of a nucleobase bound to a ribose or deoxyribose sugar via a beta-glycosidic linkage...
and 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...
. For example, they convert adenosine monophosphate to adenosine, and guanosine monophosphate
Guanosine monophosphate
Guanosine monophosphate, also known as 5'-guanidylic acid or guanylic acid and abbreviated GMP, is a nucleotide that is used as a monomer in RNA. It is an ester of phosphoric acid with the nucleoside guanosine. GMP consists of the phosphate group, the pentose sugar ribose, and the nucleobase...
to guanosine
Guanosine
Guanosine is a purine nucleoside comprising guanine attached to a ribose ring via a β-N9-glycosidic bond. Guanosine can be phosphorylated to become guanosine monophosphate , cyclic guanosine monophosphate , guanosine diphosphate , and guanosine triphosphate...
.
They have an important function in digestion
Digestion
Digestion is the mechanical and chemical breakdown of food into smaller components that are more easily absorbed into a blood stream, for instance. Digestion is a form of catabolism: a breakdown of large food molecules to smaller ones....
in that they break down consumed nucleic acids.
They can be divided into two categories, based upon the end which is hydrolyzed:
- 5'-nucleotidase - , , , ,
- 3'-nucleotidase -
5' nucleotidases cleave off the phosphate from the 5' end of the sugar moiety. They can be classified into various kinds depending on their substrate preferences and subcellular localization. Membrane bound 5' nucleotidases displays specificity towards adenosine monophosphates and are predominantly involved in the salvage of preformed nucleotides and in signal transduction cascades involving purinergic receptors. Soluble 5' nucleotidases are all known to belong to the haloacid dehalogenase superfamily of enzymes which are two domian proteins characterised by a modified Rossman fold as the core and variable cap or hood. The soluble forms are further subclassified based on the criterion mentioned above. mdN and cdN are mitochondrial and cytosolic 5'-3' pyrimidine nucleotidases. cN-I is a cytosolic nucleotidase(cN) characterized by its affinity towards AMP as its substrate.cN-II is identified by its affinity towards either IMP or GMP or both. cN-III is a pyrimidine 5' nucleotidase. 5' nucleotidases are involved in varied functions like cell-cell communication, nucleic acid repair, purine salvage pathway for the synthesis of nucleotides, signal transduction, membrane transport etc.