| 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) |
| base 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) |
| buffer pair | An acid and its conjugate base (anion). (05 Mar 2000) |
| pair | 1. To be joined in paris; to couple; to mate, as for breeding. 2. To suit; to fit, as a counterpart. "My heart was made to fit and pair with thine." (Rowe) 3. Same as To pair off. See phrase below. To pair off, to separate from a company in pairs or couples; specif., to agree with one of the opposite party or opinion to abstain from voting on specified questions or issues. See Pair. Origin: Paired; Pairing. 1. A number of things resembling one another, or belonging together; a set; as, a pair or flight of stairs. "A pair of beads." . "Four pair of stairs." . Origin: Now mostly or quite disused, except as to stairs] "Two crowns in my pocket, two pair of cards." (Beau. & Fl) 2. Two things of a kind, similar in form, suited to each other, and intended to be used together; as, a pair of gloves or stockings; a pair of shoes. 3. Two of a sort; a span; a yoke; a couple; a brace; as, a pair of horses; a pair of oxen. 4. A married couple; a man and wife. "A happy pair." . "The hapless pair." . 5. A single thing, composed of two pieces fitted to each other and used together; as, a pair of scissors; a pair of tongs; a pair of bellows. 6. Two members of opposite parties or opinion, as in a parliamentary body, who mutually agree not to vote on a given question, or on issues of a party nature during a specified time; as, there were two pairs on the final vote. 7. <physics> In a mechanism, two elements, or bodies, which are so applied to each other as to mutually constrain relative motion. Pairs are named in accordance with the kind of motion they permit; thus, a journal and its bearing form a turning pair, a cylinder and its piston a sliding pair, a screw and its nut a twisting pair, etc. Any pair in which the constraining contact is along lines or at points only (as a cam and roller acting together), is designated a higher pair; any pair having constraining surfaces which fit each other (as a cylindrical pin and eye, a screw and its nut, etc), is called a lower pair. Pair royal (pl. Pairs Royal) three things of a sort; used especially of playing cards in some games, as cribbage; as three kings, three "eight spots" etc. Four of a kind are called a double pair royal. "Something in his face gave me as much pleasure as a pair royal of naturals in my own hand." . "That great pair royal of adamantine sisters [the Fates]" . [Written corruptly parial and prial. Synonym: Pair, Flight, Set. Originally, pair was not confined to two things, but was applied to any number of equal things (pares), that go together. Ben Jonson speaks of a pair (set) of chessmen; also, he and Lord Bacon speak of a pair (pack) of cards. A "pair of stairs" is still in popular use, as well as the later expression, "flight of stairs." Origin: F. Paire, LL. Paria, L. Paria, pl. Of par pair, fr. Par, adj, equal. Cf. Apparel, Par equality, Peer an equal. 1. To unite in couples; to form a pair of; to bring together, as things which belong together, or which complement, or are adapted to one another. "Glossy jet is paired with shining white." (Pope) 2. To engage (one's self) with another of opposite opinions not to vote on a particular question or class of questions. Paired fins. <zoology> See Fin. Source: Websters Dictionary (01 Mar 1998) |
| pair bond | In animals, the social relationship established between a male and female for reproduction. It may include raising of young. (12 Dec 1998) |
| pair production | <physics> The simultaneous production of an electron and a positron by an interaction of a photon or a fast charged particle with the electronic field of a nucleus or other particle. (16 Dec 1997) |
| pair rule gene | <molecular biology> A segmentation gene, expressed sequentially between gap genes and segment polarity genes. In development of Drosophila, a set of about 8 genes that are expressed only in alternate segments (odd or even) of the developing embryo. Loss of function mutants thus lack alternate segments. Examples: even skipped (eve), fushi tarazu (ftz), hairy. (18 Nov 1997) |
| matched-pair analysis | A type of analysis in which subjects in a study group and a comparison group are made comparable with respect to extraneous factors by individually pairing study subjects with the comparison group subjects (e.g., age-matched controls). (12 Dec 1998) |