Wheat gluten protein inhibits α-amylase activity more strongly than a soy protein isolate based on kinetic analysis

Xu Chen; Xiaowei He; Bin Zhang; Lijun Sun; Zhili Liang; Qiang Huang

doi:10.1016/j.ijbiomac.2019.01.215

Wheat gluten protein inhibits α-amylase activity more strongly than a soy protein isolate based on kinetic analysis

Int J Biol Macromol. 2019 May 15:129:433-441. doi: 10.1016/j.ijbiomac.2019.01.215. Epub 2019 Feb 1.

Authors

Xu Chen¹, Xiaowei He², Bin Zhang², Lijun Sun³, Zhili Liang⁴, Qiang Huang⁵

Affiliations

¹ School of Food Science and Engineering, Guangdong Province Key Laboratory for Green Processing of Natural Products and Product Safety, South China University of Technology, Guangzhou 510640, China; School of Chemical Engineering and Energy Technology, Institute of Science and Technology Innovation, Dongguan University of Technology, Dongguan 523808, China.
² School of Food Science and Engineering, Guangdong Province Key Laboratory for Green Processing of Natural Products and Product Safety, South China University of Technology, Guangzhou 510640, China.
³ College of Food Science and Engineering, Northwest A & F University, Yangling 712100, China.
⁴ School of Food Science, Guangdong Food and Drug Vocational College, Guangzhou 510520, China.
⁵ School of Food Science and Engineering, Guangdong Province Key Laboratory for Green Processing of Natural Products and Product Safety, South China University of Technology, Guangzhou 510640, China. Electronic address: fechoh@scut.edu.cn.

PMID: 30716375
DOI: 10.1016/j.ijbiomac.2019.01.215

Abstract

The objective of this study was to investigate the porcine pancreatic α-amylase (PPA) inhibitory activity of botanical food proteins, represented by soy protein isolate (SPI) and wheat gluten protein (WGP). The half maximal inhibitory concentration (IC₅₀) was determined, and the kinetics of inhibition were investigated using Dixon, Cornish-Bowden, and Lineweaver-Burk plots. The results showed WGP functioned as mixed-type inhibitors with both competitive and uncompetitive inhibitory characteristics, while SPI showed competitive inhibitory effects on α-amylase. The competitive inhibition constants (K_ic) of WGP and SPI were 5.753 and 30.212 mg/mL, respectively, and the uncompetitive inhibition constants (K_iu) of WGP was 45.110 mg/mL, respectively. The IC₅₀ values of WGP and SPI were 3.086 and 33.899 mg/mL, respectively. For WGP, the lower K_ic vs. K_iu for mixed-type inhibitors suggested that they bound more tightly to free PPA than the PPA-starch complex. Compared with SPI, WGP displayed a stronger inhibitory effect on α-amylase. These results indicated that SPI and WGP may delay the digestion of starchy foods by inhibiting starch hydrolytic enzymes, which may be of relevance in vivo during gastrointestinal digestion. The findings are also of important practical value for the development of carbohydrate-restricted diet and protein-based functional foods.

Keywords: Botanical food protein; Enzyme inhibition; Pancreatic α-amylase; Soy protein isolate; Wheat gluten protein.

Publication types

Comparative Study

MeSH terms

Enzyme Inhibitors / pharmacology*
Glutens / pharmacology*
Hydrolysis / drug effects
Kinetics
Soybean Proteins / isolation & purification*
Soybean Proteins / pharmacology*
Starch / metabolism
Triticum / chemistry*
Zea mays / chemistry
alpha-Amylases / antagonists & inhibitors*

Substances

Enzyme Inhibitors
Soybean Proteins
Glutens
Starch
alpha-Amylases