In enzymology, a galactinol-raffinose galactosyltransferase is an enzyme that catalyzes the chemical reaction alpha-D-galactosyl--1D-myo-inositol + raffinose ⇌ {\displaystyle \rightleftharpoons } myo-inositol + stachyoseThus, the two substrates of this enzyme are α-D-galactosyl--1D-myo-inositol and raffinose, whereas its two products are myo-inositol and stachyose. Wikipedia