| u | <physics> A variable commonly used for energy density of electric or magnetic fields, also sometimes used for velocity. (09 Oct 1997) |
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| U protein | <molecular biology> Hypothetical protein thought to regulate the transition of cells from G0 to G1 phase of the cell cycle and thus inevitably into S phase. The idea would be that the concentration of this unstable (u) protein would have to exceed a threshold level for triggering progression through the cycle and that this would only happen if the cell had adequate access to growth factors or to nutrients. Synonym: trigger protein. (18 Nov 1997) |
| U wave | A positive wave following the T wave of the electrocardiogram. (05 Mar 2000) |
| u-50488 | <chemical> A nonpeptide kappa-opiod receptor agonist which has also been found to stimulate the release of adrenocorticotropin (acth) via the release of hypothalmic arginine vasopressin and corticitropin releasing factor. Pharmacological action: analgesics, non-narcotic, antihypertensive agents. (12 Dec 1998) |
| u-score method | An older, simpler, but somewhat less efficient method of linkage analysis than that by maximum likelihood estimation. (05 Mar 2000) |
| U1 small nuclear RNA-(guanosine-N2)-methyltransferase | <enzyme> A trans-active non-small nuclear ribonucleoprotein; facilitates the formation of the m3g cap Registry number: EC 2.1.1.- Synonym: u1 snrna(g-n2)mtase (26 Jun 1999) |
| u1RNA | <molecular biology> A common form of RNA that is an element of small nuclear RNA (snRNA) in the nuclei of mammalian cell, it functions to splice in or remove exons of messenger RNA. (09 Oct 1997) |
| U6 nuclease | <enzyme> Responsible for the removal of uridylates (us) specifically from the u6 3' end of the u6 small nuclear RNA Registry number: EC 3.1.13.- (26 Jun 1999) |
| U6 small nuclear RNA methyltransferase | <enzyme> Methylates gamma-phosphate residues in rnas; distinct from u6 snrna n6-adenosine methyltranferase; mw 130 kD; from hela cells Registry number: EC 2.1.1.- Synonym: u6 snrna capping enzyme (26 Jun 1999) |
| uakari | <zoology> Same as Ouakari. Source: Websters Dictionary (01 Mar 1998) |
| UAPA permease | <chemical> A uric acid-xanthine permease from aspergillus nidulans; 595 aa residues, mw 63.4 kD genbank x71807 Synonym: uapa protein, uapa gene product, uric acid-xanthine permease (26 Jun 1999) |
| UBC proteins | <protein> Family of proteins involved in conjugating ubiquitin to proteins. UBC1, UBC4 and UBC5 have a role in targeting proteins for degradation, but others have more complex roles, including an involvement in cell cycle control (UBC3) and the secretory pathway (UBC6). (18 Nov 1997) |
| ubihydroquinone | The reduction product of a ubiquinone. Synonym: ubihydroquinone. (05 Mar 2000) |
| ubiquinol | The reduction product of a ubiquinone. Synonym: ubihydroquinone. (05 Mar 2000) |
| ubiquinol-cytochrome-c reductase | <enzyme> An 11-subunit enzyme complex that acts as an electron transferring protein in the mitochondrial respiratory chain. The enzyme complex catalyses the oxidation of ubiquinol to ubiquinone and ferrocytochrome c in the presence of ferricytochrome c. It contains cytochromes b-562, b-566, and c1 as well as an iron ferredoxin. Chemical name: Ubiquinol-ferricytochrome-c oxidoreductase Registry number: EC 1.10.2.2 (12 Dec 1998) |