title: The mechanism study in the interactions of sorghum procyanidins trimer with porcine pancreatic α-amylase.
abstract: To examine the mechanisms in the interaction of sorghum procyanidins trimer (SPT) with porcine pancreatic α-amylase (PPA), fluorescence quenching, circular dichroism, and UV spectra methods were adopted. The procyanidins binding mode, binding constant and effect of procyanidins on protein stability and conformation were determined. The fluorescence spectroscopy results showed that the Stern-Volmer quenching constant K(SV) of SPT on PPA, bimolecular quenching constant k(q), and apparent static quenching constant K were 2639.5 M(-1), 2.6395 × 10(11) M(-1) s(-1), and 495.19 M(-1), respectively. In addition, binding constant KA and number of binding sites were 872.971 M(-1) and 1, respectively. Circular dichroism study revealed that PPA conformation was altered by SPT with a major reduction of β-sheet, increase of β-turn, minor change of random coil. UV spectra indicated that SPT influenced the micro-environment of aromatic amino acid residues in PPA. These findings directly elucidate the mechanisms of high molecular weight SPT in interaction with PPA.
authors.affiliation: College of Food Science and Technology, Huazhong Agricultural University, No. 1, Shizishan Street, Hongshan District, Wuhan 430070, PR China; Key Laboratory of Environment Correlative Dietology, Huazhong Agricultural University, Ministry of Education, Wuhan 430070, PR China.
authors.forename: Xin
authors.initials: X
authors.lastname: Cai
authors.affiliation: College of Food Science and Technology, Huazhong Agricultural University, No. 1, Shizishan Street, Hongshan District, Wuhan 430070, PR China; Key Laboratory of Environment Correlative Dietology, Huazhong Agricultural University, Ministry of Education, Wuhan 430070, PR China.
authors.forename: Jianan
authors.initials: J
authors.lastname: Yu
authors.affiliation: College of Food Science and Technology, Huazhong Agricultural University, No. 1, Shizishan Street, Hongshan District, Wuhan 430070, PR China.
authors.forename: Liman
authors.initials: L
authors.lastname: Xu
authors.affiliation: College of Food Science and Technology, Huazhong Agricultural University, No. 1, Shizishan Street, Hongshan District, Wuhan 430070, PR China; Key Laboratory of Environment Correlative Dietology, Huazhong Agricultural University, Ministry of Education, Wuhan 430070, PR China. Electronic address: liurui@mail.hzau.edu.cn.
authors.forename: Rui
authors.initials: R
authors.lastname: Liu
authors.affiliation: Institute of Food Sci. & Eng., Wuhan Polytechnic University, Wuhan 430023, PR China. Electronic address: junyang97@gmail.com.
authors.forename: Jun
authors.initials: J
authors.lastname: Yang
mesh_terms: D000818:Animals; D044946:Biflavonoids / Q000737:chemistry*; D002392:Catechin / Q000737:chemistry*; D055292:Pancreatic alpha-Amylases / Q000737:chemistry*; D044945:Proanthocyanidins / Q000737:chemistry*; D045868:Sorghum / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet; D013552:Swine
chemical_list: D044946:Biflavonoids; D044945:Proanthocyanidins; C017674:procyanidin; D002392:Catechin; D055292:Pancreatic alpha-Amylases
keywords: Fluorescence quenching; Interaction of polyphenol and protein; Porcine pancreatic α-amylase (PPA); Protein secondary structure; Sorghum procyanidins trimer (SPT)