Saccarosio sintasi
enzima
La saccarosio sintasi è un enzima appartenente alla classe delle transferasi, che catalizza la seguente reazione:
| saccarosio sintasi | |
|---|---|
 Modello tridimensionale dell'enzima | |
| Numero EC | 2.4.1.13 |
| Classe | Transferasi |
| Nome sistematico | |
| NDP-glucosio:D-fruttosio 2-α-D-glucosiltransferasi | |
| Altri nomi | |
| UDP-glucosio-fruttosio glucosiltransferasi; saccarosio sintetasi; saccarosio-UDP glucosiltransferasi; saccarosio-uridina difosfate glicosiltransferasi; uridina difosfoglucosio-fruttosio glucosiltransferasi | |
| Banche dati | BRENDA, EXPASY, GTD, PDB (RCSB PDB PDBe PDBj PDBsum) |
| Fonte: IUBMB | |
- NDP-glucosio + D-fruttosio ⇄ NDP + saccarosio
Sebbene l'UDP sia generalmente considerato il nucleoside difosfato preferito dalla saccarosio sintasi, tuttavia numerosi studi hanno dimostrato che l'ADP serve come molecola accettore per produrre ADP-glucosio [3-9]. La saccarosio sintasi ha un ruolo doppio in quanto produce sia l'UDP-glucosio (necessario per la sintesi della parete cellulare e delle glicoproteine) sia l'ADP-glucosio (necessario per la sintesi dell'amido) [10].
Bibliografia modifica
- Avigad, G. and Milner, Y., UDP-glucose:fructose transglucosylase from sugar beet roots, in Methods Enzymol., vol. 8, 1966, pp. 341–345.
- Cardini, C.E., Leloir, L.F. and Chiriboga, J., The biosynthesis of sucrose, in J. Biol. Chem., vol. 214, 1955, pp. 149–155, Entrez PubMed 14367373.
- Delmer, D.P., The purification and properties of sucrose synthetase from etiolated Phaseolus aureus seedlings, in J. Biol. Chem., vol. 247, 1972, pp. 3822–3828, Entrez PubMed 4624446.
- Murata, T., Sugiyama, T., Minamikawa, T. and Akazawa, T., Enzymic mechanism of starch synthesis in ripening rice grains. Mechanism of the sucrose-starch conversion, in Arch. Biochem. Biophys., vol. 113, 1966, pp. 34–44, Entrez PubMed 5941994.
- Nakai, T., Konishi, T., Zhang, X.-Q., Chollet, R., Tonouchi, N., Tsuchida, T., Yoshinaga, F., Mori, H., Sakai, F. and Hayashi, T., An increase in apparent affinity for sucrose of mung bean sucrose synthase is caused by in vitro phosphorylation or directed mutagenesis of Ser11, in Plant Cell Physiol., vol. 39, 1998, pp. 1337–1341, Entrez PubMed 10050318.
- Porchia, A.C., Curatti, L. and Salerno, G.L., Sucrose metabolism in cyanobacteria: sucrose synthase from Anabaena sp. strain PCC 7119 is remarkably different from the plant enzymes with respect to substrate affinity and amino-terminal sequence, in Planta, vol. 210, 1999, pp. 34–40, Entrez PubMed 10592030.
- Ross, H.A. and Davies, H.V., Purification and characterization of sucrose synthase from the cotyledons of Vicia fava L, in Plant Physiol., vol. 100, 1992, pp. 1008–1013.
- Silvius, J.E. and Snyder, F.W., Comparative enzymic studies of sucrose metabolism in the taproots and fibrous roots of Beta vulgaris L, in Plant Physiol., vol. 64, 1979, pp. 1070–1073.
- Tanase, K. and Yamaki, S., Purification and characterization of two sucrose synthase isoforms from Japanese pear fruit, in Plant Cell Physiol., vol. 41, 2000, pp. 408–414, Entrez PubMed 10845453.
- Baroja-Fernández, E., Muñnoz, F.J., Saikusa, T., Rodríguez-López, M., Akazawa, T. and Pozueta-Romero, J., Sucrose synthase catalyzes the de novo production of ADPglucose linked to starch biosynthesis in heterotrophic tissues of plants, in Plant Cell Physiol., vol. 44, 2003, pp. 500–509, Entrez PubMed 12773636.
