A nucleotide (nucleoside phosphate) in which the sugar component is ribose; the major ribonucleotides of RNA are adenylic acid, cytidylic acid, guanylic acid, and uridylic acid.
- r. reductase a protein complex that converts r. diphosphates (NDPs) such as ADP and CDP to 2′-deoxyribonucleotide diphosphates (dNDPs) such as dADP and dCDP. This complex requires thioredoxin, thioredoxin reductase, and NADPH. It is crucial for DNA synthesis.
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ri·bo·nu·cle·o·tide -.tīd n a nucleotide that contains ribose and occurs esp. as a constituent of RNA
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ri·bo·nu·cleo·tide (ri″bo-nooґkle-o-tīd) a nucleotide in which the purine or pyrimidine base is combined with ribose.Medical dictionary. 2011.