| nucleoside-diphosphosugar NAD+ 2-hexosyloxidoreductase | <enzyme> Oxidises udp-galactose to udp-2-ketogalactose Registry number: EC 1.1.1.- (26 Jun 1999) |
|---|---|
| nucleoside-diphosphosugar pyrophosphatase | <enzyme> Catalyses the conversion of xdp-sugar to xmp and sugar 1-phosphate Registry number: EC 3.6.1.- Synonym: ndp-sugar pyrophosphatase, nucleotide-sugar pyrophosphatase (26 Jun 1999) |
| nucleoside-monophosphate | A nucleotide, e.g., AMP. (05 Mar 2000) |
| nucleoside-phosphate kinase | <enzyme> An enzyme that catalyses reversible reactions of a nucleoside triphosphate, e.g., ATP, with a nucleoside monophosphate, e.g., ump, to form ADP and udp. Many nucleoside monophosphates can act as acceptor while many ribo- and deoxyribonucleoside triphosphates can act as donor. Chemical name: ATP:nucleoside-phosphate phosphotransferase Registry number: EC 2.7.4.4 (12 Dec 1998) |
| nucleoside-triphosphatase | <enzyme> Hydrolyzes various nucleotides to a nucleotide diphosphate + pi; inhibited by ca + ATP Registry number: EC 3.6.1.15 Synonym: nucleoside triphosphate phosphohydrolase, nucleoside triphosphatase, ntpase, nuclear envelope nucleoside triphosphatase, nuclear scaffold nucleoside triphosphatase, ns ntpase, nucleosidetriphosphatase (26 Jun 1999) |
| nucleosides | Purine or pyrimidine bases attached to a ribose or deoxyribose. (12 Dec 1998) |
| nucleoskeletal DNA | <molecular biology> DNA that is proposed to exist mostly to maintain nuclear volume and not for coding protein. (18 Nov 1997) |
| nucleosome | <cell biology> Repeating units of organisation of chromatin fibres in chromosomes, consisting of around 200 base pairs and two molecules each of the histones H2A, H2B, H3 and H4. most of the DNA (around 140 base pairs) is believed to be wound around a core formed by the histones, the remainder joins adjacent nucleosomes, thus forming a structure reminiscent of a string of beads. Origin: Gr. Soma = body (18 Nov 1997) |
| 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) |