ribosylpurine |
A toxic nucleoside isolated from the mushroom Agaricus nebularis and from Streptomyces sp. Synonym: 9-beta-ribofuranosylpurine, purine ribonucleoside, ribosylpurine. (05 Mar 2000) |
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ribosylthymidine |
5-methyluridine;the ribosyl analog of thymidine (deoxyribosylthymine); a nucleoside found in small amounts in ribonucleic acids. Synonym: ribofuranosylthymine, ribosylthymidine. (05 Mar 2000) |
ribothymidine |
5-methyluridine;the ribosyl analog of thymidine (deoxyribosylthymine); a nucleoside found in small amounts in ribonucleic acids. Synonym: ribofuranosylthymine, ribosylthymidine. (05 Mar 2000) |
ribothymidylic acid |
Ribothymidine 5'-phosphate;the ribose analog of thymidylic acid; a rare component of transfer RNAs. Acronym: TMP (05 Mar 2000) |
ribotide |
A corruption of riboside, by analogy with nucleoside-nucleotide, to mean ribonucleotide. (05 Mar 2000) |
ribotype |
The RNA complement of a cell by analogy with phenotype or genotype. (18 Nov 1997) |
ribovirus |
<virology> A virus that has RNA as itsgenetic material. (09 Oct 1997) |
ribozyme |
<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) |
ribulokinase |
<enzyme> Rn for (d)-isomer: EC 2.7.1.47 Registry number: EC 2.7.1.16 (26 Jun 1999) |
ribulose |
D-erythro-Pentulose; d-adonose; d-erythro-2-ketopentose;the 2-keto isomer of ribose. As the 5-phosphate, it participates in the pentose monophosphate shunt; as the 1,5-bisphosphate, it combines with CO2 at the start of the photosynthetic process in green plants ("carbon dioxide trap"); d-ribulose is the epimer of d-xylulose. (05 Mar 2000) |
ribulose 1,5 bisphosphate |
An intermediate in the Calvin Benson cycle of photosynthesis. (18 Nov 1997) |
ribulose bisphosphate carboxylase |
<enzyme> A copper protein that catalyses the formation of 2 moles of 3-phosphoglycerate from ribulose 1,5-biphosphate in the presence of carbon dioxide and is responsible for carbon dioxide fixation in photosynthesis. Carbon dioxide is combined with ribulose diphosphate to give two molecules of 3 phosphoglycerate, as part of the Calvin Benson cycle. It is the sole carbon dioxide fixing enzyme in C3 plants and collaborates with PEP carboxylase in carbon dioxide fixation in C4 plants. In the presence of oxygen the products of the reaction are one molecule of phosphoglyceric acid and one molecule of phosphoglycolic acid. The latter is the initial substrate for photorespiration and this oxygenase function occurs in C3 plants where the enzyme is not protected from ambient oxygen, in C4 plants the enzyme acts exclusively as a carboxylase since it is protected from oxygen. Also called Fraction 1 protein, the major protein of leaves. Chemical name: 3-Phospho-D-glycerate carboxy-lyase (dimerizing) Registry number: EC 4.1.1.39 (12 Dec 1998) |
ribulose diphosphate carboxylase |
<enzyme> A copper protein that catalyses the formation of 2 moles of 3-phosphoglycerate from ribulose 1,5-biphosphate in the presence of carbon dioxide and is responsible for carbon dioxide fixation in photosynthesis. Carbon dioxide is combined with ribulose diphosphate to give two molecules of 3 phosphoglycerate, as part of the Calvin Benson cycle. It is the sole carbon dioxide fixing enzyme in C3 plants and collaborates with PEP carboxylase in carbon dioxide fixation in C4 plants. In the presence of oxygen the products of the reaction are one molecule of phosphoglyceric acid and one molecule of phosphoglycolic acid. The latter is the initial substrate for photorespiration and this oxygenase function occurs in C3 plants where the enzyme is not protected from ambient oxygen, in C4 plants the enzyme acts exclusively as a carboxylase since it is protected from oxygen. Also called Fraction 1 protein, the major protein of leaves. Chemical name: 3-Phospho-D-glycerate carboxy-lyase (dimerizing) Registry number: EC 4.1.1.39 (12 Dec 1998) |
ribulose-1,5-bisphosphate carboxylase |
A dimerizing carboxy-lyase; an enzyme that catalyses the addition of carbon dioxide to d-ribulose 1,5-bisphosphate and the hydrolysis of the addition product to two molecules of 3-d-phosphoglyceric acid, a key reaction in the fixation of CO2 in photosynthesis. Synonym: carboxydismutase. (05 Mar 2000) |
ribulose-1,5-bisphosphate carboxylase-oxygenase large subunit epsilonN-methyltransferase |
<enzyme> An aspect of EC 2.1.1.43; trimethylates lys-14 of rubisco Registry number: EC 2.1.1.- Synonym: rubisco lsmt, rubisco large subunit lysine n-methyltransferase (26 Jun 1999) |