| ribonucleoside diphosphate reductase | <enzyme> An enzyme of the oxidoreductase class that catalyses the formation of 2'-deoxyribonucleotides from the corresponding ribonucleotides using NADPH as the ultimate electron donor. The deoxyribonucleoside diphosphates are used in DNA synthesis. Chemical name: 2'-Deoxyribonucleoside-diphosphate:oxidised-thioredoxin 2'-oxidoreductase Registry number: EC 1.17.4.1 (12 Dec 1998) |
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| ribose-1,5-diphosphate synthase | <enzyme> Uses ribose 1-(or 5)p as phosphoryl acceptor and acyl-p of 3-phosphoglyceroylphosphate as phosphoryl donor; similar reaction to glucose 1,6-bisphosphate synthase Registry number: EC 2.7.1.- Synonym: ribose-1,5-p2 synthase (26 Jun 1999) |
| 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) |
| guanosine-3',5'-bis(diphosphate) 3'-pyrophosphatase | <enzyme> Catalyses breakdown of guanosine tetraphosphate into guanosine diphosphate and pyrophosphate; spot protein is isolated from e. Coli Registry number: EC 3.1.7.2 Synonym: ppgpp-3'-pyrophosphohydrolase, guanosine tetraphosphate-3'-pyrophosphohydrolase, spot protein, spot gene product, ppgpp pyrophosphorylase, ppgppase, guanosine-5'-diphosphate 3'-diphosphate pyrophosphorylase (26 Jun 1999) |
| guanosine 5'-diphosphate | Guanosine esterified at its 5' position with diphosphoric acid; bound tightly in microtubules. Acronym: GDP (05 Mar 2000) |
| guanosine-5'-triphosphate, 3'-diphosphate pyrophosphatase | <enzyme> Catalyses the hydrolysis of guanosine 5'-triphosphate, 3'-diphosphate to yield guanosine 5'-diphosphate, 3'-diphosphate and orthophosphate; from E coli; also hydrolyzes other guanosine 5'-triphosphate derivatives with at least one unsubstituted phosphate group on the 3'-position, but not GTP, ATP or adenosine 5'-triphosphate, 3'-diphosphate Registry number: EC 3.6.1.40 Synonym: guanosine pentaphosphate phosphohydrolase, GTPdp pyrophosphatase, pppgpp 5'-phosphohydrolase, guanosine 5'-triphosphate-3'diphosphate 5'-phosphohydrolase, pppgpp-5'-phosphohydrolase, pppgpp-5'-phosphatase (26 Jun 1999) |
| guanosine 5'-triphosphate 3'-diphosphate pyrophosphorylase | <enzyme> Yields pyrophosphate + pppg Registry number: EC 2.7.7.- Synonym: pppgpp pyrophosphorylase (26 Jun 1999) |
| guanosine diphosphate | A molecule which consists of the nitrogenous base guanine linked to the sugar ribose and which has two phosphate groups attached to the 5th carbom atom of the ribose. It is a derivative of the ribonucleotide GMP. (09 Oct 1997) |
| guanosine diphosphate fucose | <chemical> A nucleoside diphosphate sugar formed from GDPmannose, which provides fucose for lipopolysaccharides of bacterial cell walls, and for blood group substances and other glycoproteins. Chemical name: Guanosine 5'-(trihydrogen diphosphate), P'-(6-deoxy-beta-L-galactopyranosyl) ester (12 Dec 1998) |
| guanosine diphosphate mannose | <chemical> A nucleoside diphosphate sugar which can be converted to the deoxy sugar GDPfucose, which provides fucose for lipopolysaccharides of bacterial cell walls. Also acts as mannose donor for glycolipid synthesis. Chemical name: Guanosine 5'-(trihydrogen diphosphate), mono-alpha-D-mannopyranosyl ester (12 Dec 1998) |
| guanosine diphosphate sugars | Esters formed between the aldehydic carbon of sugars and the terminal phosphate of guanosine diphosphate. (12 Dec 1998) |
| phosphatidylinositol 4,5-diphosphate | <biochemistry> A phosphoinositide present in all eukaryotic cells, particularly in the plasma membrane. It is the major substrate for receptor-stimulated phosphoinositidase c, with the consequent formation of inositol 1,4,5-triphosphate and diacylglycerol, and probably also for receptor-stimulated inositol phospholipid 3-kinase. (12 Dec 1998) |
| poly adenosine diphosphate ribose | <chemical> A polynucleotide formed from NAD in the presence of NAD+ nucleosidase. Chemical name: Adenosine 5'-(trihydrogen diphosphate), P'-5-ester with D-ribose, homopolymer (12 Dec 1998) |
| cytidine 5'-diphosphate | <biochemistry> An ester, at the 5' position, between cytidine and diphosphoric acid. It is derived from cytidine 5'-triphosphate and is important in phosphatide biosynthesis. Acronym: CDP (21 Jun 2000) |
| cytidine diphosphate | <chemical> Cytidine 5'-(trihydrogen diphosphate). A cytosine nucleotide containing two phosphate groups esterified to the sugar moiety. Synonym: crpp; cytidine pyrophosphate. Chemical name: Cytidine 5'-(trihydrogen diphosphate) (12 Dec 1998) |