| 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 phosphorylase | <enzyme> From klebsiella sp.; acts on both purine and pyrimidine nucleosides and catalyses the production of araa from uridine arabinoside (arau) and adenine Registry number: EC 2.4.2.- (26 Jun 1999) |
| nucleoside phosphorylases | Enzymes that catalyze the phosphorolysis of a nucleoside, forming the free purine or pyrimidine plus ribose (or deoxyribose 1-phosphate); e.g., purine-nucleoside phosphorylases. (05 Mar 2000) |
| nucleoside q | <chemical> (1s-(1 alpha,4 beta,5 beta))-2-amino-5-(((4,5-dihydroxy-2-cyclopenten-1-yl)amino)methyl)-1,7-dihydro-7-beta-d-ribofuranosyl-4h-pyrrolo(2,3-d)pyrimidin-4-one. A modified nucleoside which is present in the first position of the anticodon of trna-tyrosine, trna-histidine, trna-asparagine and trna-aspartic acid of many organisms. It is believed to play a role in the regulatory function of trna. Nucleoside q can be further modified to nucleoside q*, which has a mannose or galactose moiety linked to position 4 of its cyclopentenediol moiety. Chemical name: 4H-Pyrrolo(2,3-d)pyrimidin-4-one, 2-amino-5-(((4,5-dihydroxy-2-cyclopenten-1-yl)amino)methyl)-1,7-dihydro-7-beta-D-ribofuranosyl-, (1S-(1alpha,4beta,5beta))- (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) |
| nucleoside triphosphate | A nucleoside in which the H of one of the ribose hydroxyls (usually the 5') is replaced by a triphosphoric group, -PO(OH)-O-PO(OH)-O-PO(OH)2; e.g., adenosine triphosphate. (05 Mar 2000) |
| nucleoside triphosphate-adenylate kinase | <enzyme> Other nucleoside triphosphates may replace GTP as substrate Registry number: EC 2.7.4.10 Synonym: GTP-AMP phosphotransferase, AMP-GTP phosphotransferase (26 Jun 1999) |
| active transport | <biochemistry, chemistry> Transport of ions, nutrients or other molecules into a cell against a concentration gradient, this requires the expenditure of energy through ATP hydrolysis. (06 May 1997) |
| anterograde transport | Movement of material from the cell body of a neuron into axons and dendrites retrograde axoplasmic transport also occurs). (18 Nov 1997) |
| atrial transport function | The role of the atria in filling and stretching the ventricles by their presystolic contraction, without which the force of ventricular contraction and hence the cardiac output may significantly decrease. (05 Mar 2000) |
| axonal transport | Directed transport of organelles and molecules along a nerve cell axon. Transport can be anterograde (from the cell body) or retrograde (toward the cell body). (alberts et al., molecular biology of the cell, 3d ed, pg3) (12 Dec 1998) |
| axoplasmic transport | Transport by way of flow of axoplasm toward cell soma (retrograde) or toward axon terminal (anterograde). (05 Mar 2000) |