Reaction: UDP-α-D-glucose + D-fructose 6-phosphate = UDP + sucrose 6F-phosphate
Other name(s): UDP-glucose—fructose-phosphate glucosyltransferase; sucrosephosphate—UDP glucosyltransferase; UDP-glucose-fructose-phosphate glucosyltransferase; SPS; uridine diphosphoglucose-fructose phosphate glucosyltransferase; sucrose 6-phosphate synthase; sucrose phosphate synthetase; sucrose phosphate-uridine diphosphate glucosyltransferase; sucrose phosphate synthase
Systematic name: UDP-α-D-glucose:D-fructose-6-phosphate 2-α-D-glucosyltransferase (configuration-retaining)
Comments: Requires Mg2+ or Mn2+ for maximal activity [2]. The enzyme from Synechocystis sp. strain PCC 6803 is not specific for UDP-glucose as it can use ADP-glucose and, to a lesser extent, GDP-glucose as substrates [2]. The enzyme from rice leaves is activated by glucose 6-phosphate but that from cyanobacterial species is not [2]. While the reaction catalysed by this enzyme is reversible, the enzyme usually works in concert with EC 3.1.3.24, sucrose-phosphate phosphatase, to form sucrose, making the above reaction essentially irreversible [3]. The F in sucrose 6F-phosphate is used to indicate that the fructose residue of sucrose carries the substituent.
Links to other databases: BRENDA, EXPASY, GTD, KEGG, Metacyc, PDB, CAS registry number: 9030-06-2
References:
1. Mendicino, J. Sucrose phosphate synthesis in wheat germ and green leaves. J. Biol. Chem. 235 (1960) 3347-3352. [PMID: 13769376]
2. Curatti, L., Folco, E., Desplats, P., Abratti, G., Limones, V., Herrera-Estrella, L. and Salerno, G. Sucrose-phosphate synthase from Synechocystis sp. strain PCC 6803: identification of the spsA gene and characterization of the enzyme expressed in Escherichia coli. J. Bacteriol. 180 (1998) 6776-6779. [PMID: 9852031]
3. Huber, S.C. and Huber, J.L. Role and regulation of sucrose-phosphate synthase in higher plants. Annu. Rev. Plant Physiol. Plant Mol. Biol. 47 (1996) 431-444. [PMID: 15012296]
4. Cumino, A., Curatti, L., Giarrocco, L. and Salerno, G.L. Sucrose metabolism: Anabaena sucrose-phosphate synthase and sucrose-phosphate phosphatase define minimal functional domains shuffled during evolution. FEBS Lett. 517 (2002) 19-23. [PMID: 12062401]
5. Chua, T.K., Bujnicki, J.M., Tan, T.C., Huynh, F., Patel, B.K. and Sivaraman, J. The structure of sucrose phosphate synthase from Halothermothrix orenii reveals its mechanism of action and binding mode. Plant Cell 20 (2008) 1059-1072. [PMID: 18424616]