Isolation and Identification of Oligosaccharides Produced from Raffinose by Transgalactosylation Reaction of Thermostable α-Galactosidase from Pycnoporus cinnabarinus

Abstract

The thermostable α-galactosidase purified from Pycnoporus cinnabarinus catalyzed the galactosyltransfer reaction in the hydrolysis of raffinose and produced several kinds of transfer products. The main transfer products were isolated and the structures of the six kinds of transfer products (oligosaccharides A, B, C, D, E, and F) were investigated by acid and enzymatic hydrolysis, and methylation analysis. Oligosaccharides A, B, C, D, E, and F were identified as O-α-D-galactopyranosyl-(1→3)-O-α-D-glucopyranosyl-(1→2)-β-D-fructofuranoside, O-α-D-galactopyranosyl-(1→3)-O-α-D-galactopyranosyl-(1→6)-O-α-D-glucopyranosyl-(1→2)-β-D-fructofuranoside, stachyose, O-α-D-galactopyranosyl-(1→3)-O-α-D-galactopyranosyl-(1→6)-O-α-D-galactopyranosyl-(1→6)-O-α-D-glucopyranosyl-(1→2)-β-D-fructofuranoside, verbascose, and ajugose, respectively.