| RPG | radiation protection guide; Report Program Generator[ PC language]; retrograde pyelogram; rheoplethy... |
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| RNA, catalytic | RNA which contains an intron sequence that has an enzyme-like catalytic activity. This intron sequence has been shown to fold up to form a complex surface that can function like an enzyme in reactions with other RNA molecules and thus synthesise new molecules even in the absence of protein. (12 Dec 1998) |
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| RNA, chloroplast | Ribonucleic acid in chloroplasts having regulatory and catalytic roles as well as involvement in protein synthesis. (12 Dec 1998) |
| RNA, complementary | Synthetic transcripts of a specific DNA molecule or fragment, made by an in vitro transcription system. This crna can be labelled with radioactive uracil and then used as a probe. (12 Dec 1998) |
| RNA-dependent ATPase | <enzyme> Requires single-stranded polynucleotide as cofactor Registry number: EC 3.6.1.- Synonym: atpase, RNA-dependent (26 Jun 1999) |
| RNA-directed DNA polymerase | <enzyme> An enzyme that synthesises DNA on an RNA template. It is encoded by the pol gene of retroviruses and by certain retrovirus-like elements. Chemical name: Deoxynucleotide-triphosphate:DNA deoxynucleotidyltransferase (RNA-directed) Registry number: EC 2.7.7.49 (12 Dec 1998) |
| RNA, double-stranded | RNA consisting of two strands as opposed to the more prevalent single-stranded RNA. most of the double-stranded segments are formed from transcription of DNA by intramolecular base-pairing of inverted complementary sequences separated by a single-stranded loop. Some double-stranded segments of RNA are normal in all organisms. (12 Dec 1998) |
| RNA editing | <molecular biology> Specific alterations of RNAs, for example C_V changes that are not coded for in the genes. (23 Aug 1998) |
| RNA enzyme | <molecular biology> Often referred to as RNA with catalytic capacity, an enzyme made of nucleic acid not protein that catalyse chemical reactions, often the breakdown of other RNAs. Of particular interest because of the implications for self replicating systems in the earliest stages of the evolution of (terrestrial) life. Their discovery in the mid-1980s refuted the concept that only proteins could be biological catalysts. There is potential for their use as pharmaceuticals and industrial catalysts. (13 Nov 1997) |
| RNA, fungal | Ribonucleic acid in fungi having regulatory and catalytic roles as well as involvement in protein synthesis. (12 Dec 1998) |
| RNA helicase | <enzyme> Nuclear envelope-associated RNA helicase activity in nucleocytoplasmic RNA transport; both glh-1 and glh-2 contain cchc-type zinc fingers; xp54 is xenopus homologue of human RNA helicase p54 Registry number: EC 2.7.7.- Synonym: RNA duplex unwindase, p54 gene product, bat1 gene product, RNA helicase a, rok1 protein, human RNA helicase 1, hrh1 protein, mrdb protein, glh-1 protein, glh-2 protein, RNA helicase p54, xp54, u5 snrnp-specific 100-kD protein (26 Jun 1999) |
| RNA, helminth | Ribonucleic acid in helminths having regulatory and catalytic roles as well as involvement in protein synthesis. (12 Dec 1998) |
| RNA, heterogeneous nuclear | Nuclear nonribosomal RNA larger than about 1000 nucleotides, the mass of which is rapidly synthesised and degraded within the cell nucleus. Some heterogeneous nuclear RNA may be a precursor to mRNA. However, the great bulk of total hnrna hybridises with nuclear DNA rather than with mRNA. (12 Dec 1998) |
| RNA life | <biology, molecular biology> A hypothetical life form lacking DNA and protein which may have existed on early earth and in which RNA served both a genetic coding and a catalytic function. (23 Aug 1998) |
| RNA ligase | <enzyme> An enzyme that catalyses the conversion of linear RNA to a circular form by the transfer of the 5'-phosphate to the 3'-hydroxyl terminus. It also catalyses the covalent joining of two polyribonucleotides in phosphodiester linkage. Chemical name: Poly(ribonucleotide):poly(ribonucleotide)ligase (AMP-forming) Registry number: EC 6.5.1.3 (12 Dec 1998) |
| RNA N-glycosidase | <enzyme> Catalyses hydrolysis of a single adenosine glycosidic bond; probable cause of toxic effect of vero toxin from E coli by inactivating 60s ribosomal subunit Registry number: EC 3.2.2.- Synonym: RNA glycosylase (26 Jun 1999) |