3 or 3’-Galloyl substitution plays an important role in association of catechins and theaflavins with porcine pancreatic α-amylase: The kinetics of inhibition of α-amylase by tea polyphenols

Sun, Lijun, Warren, Fredrick J., Netzel, Gabriele and Gidley, Michael J. (2016) 3 or 3’-Galloyl substitution plays an important role in association of catechins and theaflavins with porcine pancreatic α-amylase: The kinetics of inhibition of α-amylase by tea polyphenols. Journal of Functional Foods, 26 144-156. doi:10.1016/j.jff.2016.07.012


Author Sun, Lijun
Warren, Fredrick J.
Netzel, Gabriele
Gidley, Michael J.
Title 3 or 3’-Galloyl substitution plays an important role in association of catechins and theaflavins with porcine pancreatic α-amylase: The kinetics of inhibition of α-amylase by tea polyphenols
Journal name Journal of Functional Foods   Check publisher's open access policy
ISSN 1756-4646
2214-9414
Publication date 2016-10
Year available 2016
Sub-type Article (original research)
DOI 10.1016/j.jff.2016.07.012
Open Access Status Not yet assessed
Volume 26
Start page 144
End page 156
Total pages 13
Place of publication Amsterdam, Netherlands
Publisher Elsevier BV
Collection year 2017
Language eng
Formatted abstract
The inhibitory activities of three tea extracts (TEs) and individual phenolic compounds in TEs against porcine pancreatic α amylase (PPA) were studied by measuring their half inhibitory (IC50) concentrations. The kinetics of inhibition by these extracts and compounds were investigated through Dixon, Cornish-Bowden, and Lineweaver–Burk plots. The results showed that green, oolong and black tea extracts, epigallocatechin gallate, theaflavin-3, 3′- digallate and tannic acid were competitive inhibitors of PPA, whereas epicatechin gallate, theaflavin-3′-gallate and theaflavin were mixed-type inhibitors with both competitive and uncompetitive inhibitory characteristics. Only catechins with a galloyl substituent at the 3-position showed measurable inhibition. The competitive inhibition constants (Kic) were lower for theaflavins than catechins, with the lowest value for theaflavin-3, 3′-digallate. The lower Kic than the uncompetitive inhibition constant for the mixed-type inhibitors suggests that they bind more tightly with free PPA than with the PPA–starch complex. A 3 and/ or 3′-galloyl moiety in catechin and theaflavin structures was consistently found to increase inhibition of PPA through enhanced association with the enzyme active site.
Keyword Tea polyphenols
α-amylase
Inhibition
Kinetics
Galloyl moiety
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: HERDC Pre-Audit
Queensland Alliance for Agriculture and Food Innovation
 
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Created: Mon, 01 Aug 2016, 09:22:04 EST by Lijun Sun on behalf of Qld Alliance for Agriculture and Food Innovation