| MMPNC | Medical Maternal Program for Nuclear Casualties |
|---|---|
| MNS | medial nuclear stratum; Melnick-Needles syndrome; moesin |
| NA | Avogadro constant or number; nalidixic acid; Narcotics Anonymous; network administrator; neuraminida... |
| N:C | nuclear-cytoplasmic ratio |
| NCA | National Certification Agency; National Council on Aging; National Council on Alcoholism; neurocircu... |
| 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, guide | Small kinetoplastid mitochondrial RNA that plays a major role in RNA editing. These molecules form perfect hybrids with edited mRNA sequences and possess nucleotide sequences at their 5'-ends that are complementary to the sequences of the mRNA's immediately downstream of the pre-edited regions. (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 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) |
| RNA nucleotidyltransferases | <enzyme> Enzymes that catalyze the template-directed incorporation of ribonucleotides into an RNA chain. Registry number: EC 2.7.7. (12 Dec 1998) |
| RNA phages | Bacteriophages whose genetic material is RNA, which is single-stranded in all except the pseudomonas phage phi6. All RNA phages infect their host bacteria via the host's surface pili. Some frequently encountered RNA phages are: qbeta, ms2, bf23, f2, r17, fr, mu2, phicb5, phicb12r, phicb8r, phicb23r, 7s, phi6, pp7. (12 Dec 1998) |
| RNA, plant | Ribonucleic acid in plants having regulatory and catalytic roles as well as involvement in protein synthesis. (12 Dec 1998) |
| RNA plasmid | <molecular biology> DsRNA found in yeasts, also called killer factors. Their nomenclature is uncertain and some scientists consider them viruses. (23 Aug 1998) |
| RNA polymerase | <enzyme, molecular biology> An enzyme that polymerise ribonucleotides in accordance with the information present in DNA. Prokaryotes have a single enzyme for the three RNA types that is subject to stringent regulatory mechanisms. Eukaryotes have type I that synthesises all rRNA except the 5S component, type II that synthesises mRNA and hnRNA and type III that synthesises tRNA and the 5S component of rRNA. (23 Aug 1998) |
| RNA polymerase I | <enzyme> A DNA-dependent RNA polymerase present in bacterial, plant, and animal cells. The enzyme functions in the nucleolar structure and transcribes DNA into RNA. It has different requirements for cations and salts than RNA polymerase II and III and is not inhibited by alpha-amanitin. Registry number: EC 2.7.7.- (12 Dec 1998) |
| RNA polymerase II | <enzyme> A DNA-dependent RNA polymerase present in bacterial, plant, and animal cells. It functions in the nucleoplasmic structure and transcribes DNA into RNA. It has different requirements for cations and salt than RNA polymerase I and is strongly inhibited by alpha-amanitin. Registry number: EC 2.7.7.- (12 Dec 1998) |