Stachyose, biosynthesis

In the crude extract of the ripening bean seeds, an enzyme is also present that transfers the D-galactosyl- C group from UDP-D-galac-tose- C, but not from ADP-D-galactose- C, to mi/o-inositol. This enzyme had previously been found in extracts of pea seeds. The biosynthesis of stachyose is, therefore, assumed to occur by the following reactions. 

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