| ribo- | 1. Ribose. 2. As an italicised prefix to the systematic name of a monosaccharide, ribo-indicates that the configuration of a set of three consecutive, but not necessarily contiguous, CHOH (or asymmetric) groups is that of ribose; e.g., d-ribose, a trivial name, is d-ribo-pentose in systematic nomenclature. Origin: German Ribose (05 Mar 2000) |
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| ribo-2-hexulose | Ribo-2-hexulose;a ketohexose; d-psicose is epimeric with d-fructose. Synonym: pseudofructose, ribo-2-hexulose. (05 Mar 2000) |
| riboflavin | <biochemistry> Ribose attached to a flavin moiety that becomes part of FAD and FMN. (23 Aug 1998) |
| riboflavin 5'-phosphate | <biochemistry> This biomolecule serves as a coenzyme for some enzymes that catalyse oxidation-reduction reactions. (09 Oct 1997) |
| riboflavin deficiency | A dietary deficiency of riboflavin causing a syndrome chiefly marked by cheilitis, angular stomatitis, glossitis associated with a purplish red or magenta-coloured tongue that may show fissures, corneal vascularization, dyssebacia, and anaemia. (12 Dec 1998) |
| riboflavin kinase | A cytosolic enzyme catalyzing the formation of flavin mononucleotide (r. Phosphate) from riboflavin, utilizing ATP as phosphorylating agent. Synonym: flavokinase. (05 Mar 2000) |
| riboflavin permease | <chemical> Chemical name: permease, riboflavin (26 Jun 1999) |
| riboflavin synthase | <enzyme> An enzyme that catalyses the formation of riboflavin from two molecules of 6,7-dimethyl-8-ribityllumazine, utilizing a four-carbon fragment from one molecule which is transferred to the second molecule. Chemical name: 6,7-Dimethyl-8-(1-D-ribityl)lumazine:6,7-dimethyl-8-(1-D-ribityl)lumazine 2,3-butanediyltransferase Registry number: EC 2.5.1.9 (12 Dec 1998) |
| riboflavin unit | Potency usually expressed in terms of weight of pure riboflavin. See: Sherman-Bourquin unit of vitamin B2. Synonym: vitamin B2 unit. (05 Mar 2000) |
| riboflavinoid | <biochemistry> Member of the water soluble B vitamin group, important in energy production and the production of red blood cells (23 Aug 1998) |
| ribofuranose | The 1,4 cyclic furan form of ribose. (05 Mar 2000) |
| ribofuranosylthymine | 5-methyluridine;the ribosyl analog of thymidine (deoxyribosylthymine); a nucleoside found in small amounts in ribonucleic acids. Synonym: ribofuranosylthymine, ribosylthymidine. (05 Mar 2000) |
| ribokinase | <enzyme> Substrate ribose may be replaced by deoxyribose Registry number: EC 2.7.1.15 Synonym: deoxyribokinase (26 Jun 1999) |
| ribonuclease | <biochemistry, enzyme, molecular biology> Widely distributed type of enzyme that cleaves RNA. May act as endonucleases or exonucleases depending upon the type of enzyme. Generally recognise target by tertiary structure rather than sequence. Ribonuclease E is involved in the formation of 5S ribosomal RNA from pre rRNA. Ribonuclease F is stimulated by interferons and cleaves viral and host RNA and thus inhibits protein synthesis. Ribonuclease H specifically cleaves an RNA base paired to a complementary DNA strand. Ribonuclease P is an endonuclease that generate t RNA from their precursor transcripts. Ribonuclease T is an endonuclease that removes the terminal AMP from the 3' CCA end of a nonaminoacylated tRNA. Ribonuclease T1 cleaves RNA specifically at guanosine residues. Ribonuclease TIII cleaves double stranded regions of RNA molecules. Acronym: RNase (23 Aug 1998) |
| ribonuclease (Bacillus subtilis) | 1. Ribonuclease (Azotobacter agilis); ribonuclease (Proteus mirabilis); an enzyme catalyzing the endonucleolytic cleavage of RNA to yield 2',3'-cyclic nucleotides. 2. Ribonuclease T1. (05 Mar 2000) |