| nucleosomes | The repeating structural units of chromatin, each consisting of approximately 200 base pairs of DNA wound around a protein core. This core is composed of the histones h2a, h2b, h3, and h4. (12 Dec 1998) |
|---|---|
| nucleospindle | The fusiform body in mitosis. (05 Mar 2000) |
| nucleotidase | <enzyme> Catalyses dephosphorylation of ribonucleoside 5'-monophosphates, ribonucleoside 3'-monophosphates and deoxyribonucleoside 3'-monophosphates Registry number: EC 3.1.3.31 Synonym: deoxyinosine-activated nucleotidase, nucleotide phosphohydrolase, cytosolic deoxyribonucleotide-activated nucleotidase, da-nucleotidase (26 Jun 1999) |
| nucleotidases | <enzyme> A class of enzymes that catalyze the conversion of a nucleotide and water to a nucleoside and orthophosphate. Registry number: EC 3.1.3.- (12 Dec 1998) |
| nucleotide | <biochemistry> Phosphate esters of nucleosides. The metabolic precursors of nucleic acids are monoesters with phosphate on carbon 5 of the pentose (known as 5' to distinguish sugar from base numbering). However many other structures, such as adenosine 3'5' cyclic monophosphate (cAMP) and molecules with 2 or 3 phosphates are also called nucleotides. (18 Nov 1997) |
| nucleotide 3'-pyrophosphokinase-2',3'-cyclic monophosphokinase | <enzyme> Transfers 5'-beta,gamma-pyrophosphate from ATP and some ATP derivatives to nucleotides and nucleosides at the 3'-hydroxyl group; synthesises the respective 3'-pyrophosphoryl nucleotides Registry number: EC 2.7.6.- Synonym: ppkase (26 Jun 1999) |
| nucleotide binding fold | Protein motif consisting of a fold or pocket with certain conserved residues, required for the binding of nucleotides. (18 Nov 1997) |
| nucleotide deaminases | <enzyme> Catalyze the hydrolysis of nucleotides with the elimination of ammonia. Registry number: EC 3.5.4 (12 Dec 1998) |
| nucleotide deletion | Deletion of a single nucleotide, which in a transcribed gene will lead to a frameshift mutation. Synonym: point deletion. (05 Mar 2000) |
| nucleotide mapping | Two-dimensional separation and analysis of nucleotides. (12 Dec 1998) |
| nucleotide pair | <molecular biology> Two nitrogenous bases (adenine and thymine or guanine and cytosine) held together by weak bonds. Two strands of DNA are held together in the shape of a double helix by the bonds between base pairs. (09 Oct 1997) |
| nucleotide phosphotransferase | <enzyme> Transfers phosphoric acid from an organic phosphate donor to the 2' or 3' hydroxyls of nucleosides and nucleotides Registry number: EC 2.7.1.- (26 Jun 1999) |
| nucleotide pyrophosphate transferase | <enzyme> Transfers the beta, gamma pyrophosphate group from ATP to 3'-hydroxy group of ribonucleotides, oligonucleotides or trna Registry number: EC 2.7.6.- (26 Jun 1999) |
| nucleotides | The basic building blocks of nucleic acids. They are made up of a nitrogen-containing purine or pyrimidine base linked to a sugar (ribose or deoxyribose) and a phosphate group. (14 Nov 1997) |
| nucleotidyltransferases | <enzyme> A class of enzymes that transfers nucleotidyl residues. Registry number: EC 2.7.7 (12 Dec 1998) |