Abstract:

The effect of (–)-epigallocatechin-3-gallate (EGCG) on the structure-activity relationship of pancreatic lipase
was studied in this work. The secondary and tertiary structures of pancreatic lipase were measured by circular dichroism
(CD) and fluorescence spectroscopes (FS), respectively. Using olive oil as the substrate, the activity of pancreatic lipase as a
function of incubation time and EGCG concentration was also investigated. The results showed that the maximum inhibitory
rate was observed after 1 h mixing of EGCG with pancreatic lipase. The inhibitory rate rapidly increased with increasing
EGCG concentration up to 1 mmol/L and then remained basically unchanged as the EGCG concentration continued to
increase. The Lineweaver-Burk plot showed that EGCG non-competitively inhibited the activity of pancreatic lipase. CD
and FS analyses suggested that EGCG influenced both the secondary and tertiary structures of pancreatic lipase, and its
concentraiton was positively correlated with the secondary structure but had no significant correlation with the tertiary
structure. FS analyses also indicated that EGCG quenched the Trp fluorescence of pancreatic lipase statically or dynamically.

Key words: pancreatic lipase；(&ndash, )-epigallocatechin-3-gallate；structure-activity relationship；circular dichroism spectroscopy； fluorescence spectroscopy