Inhibition of cyclodextrins on α-galactosidase

• Cyclodextrins (CDs)-α-galactosidase interactions were observed for the first time.
• α-Gal inhibition of approximately 36% for α-CD, 81% for β-CD and 40% for γ-CD.
• Strongest inhibition of α-galactosidase (α-Gal) induced by β-cyclodextrin β-CD.
• Formation of hydrogen bond in α-Gal after interaction with β-CD.

This work successfully investigated the effects of different influential factors and hydrophobic cavities of cyclodextrins (CDs) on α-galactosidase (α-Gal) by detecting α-Gal activity. The highest inhibitory concentration of three kinds of CDs (α-, β-, and γ-CD) on α-Gal was 10 mM. Moreover, the highest inhibition of α-Gal was obtained under the following conditions: reaction time of 90 min, temperature of 30 °C, and pH 6.0. Compared with other CDs, β-CD showed more ability to interact with α-Gal due to its appropriate cavity geometric dimensions. From circular dichroism and nuclear magnetic resonance it was observed that β-CD changed the secondary structure of α-Gal and formed a hydrogen bond with this enzyme.