Galactinol—raffinose galactosyltransferase

In enzymology, a galactinol-raffinose galactosyltransferase is an enzyme that catalyzes the chemical reaction


 * alpha-D-galactosyl-(1→3)-1D-myo-inositol + raffinose $$\rightleftharpoons$$ myo-inositol + stachyose

Thus, the two substrates of this enzyme are α-D-galactosyl-(1→3)-1D-myo-inositol and raffinose, whereas its two products are myo-inositol and stachyose.

This enzyme participates in galactose metabolism.

Nomenclature
This enzyme belongs to the family of glycosyltransferases, specifically the hexosyltransferases. The systematic name of this enzyme class is alpha-D-galactosyl-(1→3)-myo-inositol:raffinose galactosyltransferase. Other names in common use include galactinol-raffinose galactosyltransferase, and stachyose synthetase.