MetaCyc Enzyme: raffinose synthase

Synonyms: galactinol:sucrose 6-galactosyltransferase

Species: Vicia faba

A raffinose synthase (RFS) was purified 400-fold from maturing seeds of Vicia faba [Lehle73]. The protein was shown to catalyze the transfer of the galactosyl moiety of galactinol to sucrose, leading to the formation of raffinose and myo-inositol. The chemical properties, inhibitors and substrate specificity of the enzyme were determined.

Molecular Weight of Polypeptide: 80 kD (experimental) [Lehle73]

Gene-Reaction Schematic

Gene-Reaction Schematic

Enzymatic reaction of: raffinose synthase

Inferred from experiment

EC Number:

galactinol + sucrose → myo-inositol + raffinose

The direction shown, i.e. which substrates are on the left and right sides, is in accordance with the Enzyme Commission system.

The reaction is favored in the direction shown.

In Pathways: stachyose biosynthesis

Inhibitors (Other): Ag+ [Lehle73], Hg2+ [Lehle73], Zn2+ [Lehle73], Al3+ [Lehle73], Mn2+ [Lehle73]Kinetic Parameters:
Substrate Km (μM) Citations
galactinol 1000.0 [Lehle73]
raffinose 10000.0 [Lehle73]
sucrose 2900.0 [Lehle73]

T(opt): 42 °C [Lehle73]

pH(opt): 7.0 [Lehle73]


Lehle73: Lehle L, Tanner W (1973). "The function of myo-inositol in the biosynthesis of raffinose. Purification and characterization of galactinol:sucrose 6-galactosyltransferase from Vicia faba seeds." Eur J Biochem 38(1);103-10. PMID: 4774118

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Please cite the following article in publications resulting from the use of MetaCyc: Caspi et al, Nucleic Acids Research 42:D459-D471 2014
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