Revealing the mechanisms of starch amylolysis affected by tea catechins using surface plasmon resonance

The interaction of polyphenolic catechins from Camellia sinensis tea with α-amylase, and the effects of the interactions on the kinetics of starch amylolysis, were investigated. Binding studies using surface plasmon resonance (SPR) and enzyme kinetic analysis indicated that the in vitro digestibility of gelatinized wheat starch was decreased by the addition of catechins present in tea. Tea catechins decreased enzyme activity by reducing the maximum velocity (V_max) of the α-amylase, but had little effect on the Michaelis-Menten constant (K_m). Binding studies by SPR showed that the structure of the catechins influenced their affinity for α-amylase. Pearson correlation analysis showed that the decreased digestibility of starch in the presence of catechins was due to their binding of α-amylase interaction inhibiting the catalytic effectiveness of the enzyme. From this study, we concluded that the faster and stronger the binding of catechins and α-amylase, the greater reduction of starch digestion is.