Inhibitory Effect of 0.19  -Amylase Inhibitor from Wheat Kernel on the Activity of Porcine Pancreas  -Amylase and Its Thermal Stability

Abstract

The inhibitory effect of 0.19 alpha-amylase inhibitor (0.19 AI) from wheat kernel on the porcine pancreas alpha-amylase (PPA)-catalyzed hydrolysis of p-nitrophenyl-alpha-D-maltoside (pNP-G2) was examined. 0.19 AI is a homodimer of 26.6 kDa with 13.3-kDa subunits under the conditions used. The elution behaviors in gel filtration HPLC of PPA and 0.19 AI indicated that a PPA molecule bound with a 0.19 AI molecule (homodimer) at a molar ratio of 1:1. 0.19 AI inhibited PPA activity in a competitive manner with an inhibitor constant, K(i), of 57.3 nM at pH 6.9, 30 degrees C, and the binding between them was found to be endothermic and entropy-driven. The activation energy for the thermal inactivation of 0.19 AI was determined to be 87.0 kJ/mol, and the temperature, T(50), giving 50% inactivation in a 30-min incubation at pH 6.9 was 88.1 degrees C. The high inhibitory activity of 0.19 AI against PPA and its high thermal stability suggest its potential for use in the prevention and therapy of obesity and diabetes.

Inhibitory effects of chlorogenic acids from green coffee beans and cinnamate derivatives on the activity of porcine pancreas α-amylase isozyme I

“…Inhibition of PPA-I by CGAs using G 2 -pNP as substrate PPA-I hydrolyses G 2 -pNP to produce p-nitrophenol (pNP) and maltose (Oneda et al, 2004). Hydrolysis of G 2 -pNP by 0.8 lM PPA-I in 20 mM sodium phosphate buffer (pH 6.9, buffer B) containing 25 mM NaCl was measured continuously following the increase in absorbance at 400 nm due to pNP at 20-40°C.…”

“…Hydrolysis of G 2 -pNP by 0.8 lM PPA-I in 20 mM sodium phosphate buffer (pH 6.9, buffer B) containing 25 mM NaCl was measured continuously following the increase in absorbance at 400 nm due to pNP at 20-40°C. The amount of pNP was evaluated using the molar absorption coefficient of 9.47 mM À1 cm À1 at pH 6.9 (Oneda et al, 2004). The molecular activity (k cat ) and Michaelis constant (K m ) were calculated from Hanes-Woolf plots (Segel, 1975).…”

“…FFI from chestnut astringent skin extract was reported to suppress the rise in plasma glucose level after boiled-rice loading in a dose-dependent manner in humans (Tsujita, Yakaku, & Suzuki, 2008). Various FFIs, such as acarbose (Al Kazaz, Desseaux, Marchis-Mouren, Prodanov, & Santimone, 1998) and protein FFI from wheat kernel (Oneda, Lee, & Inouye, 2004), are discussed in the inhibition mechanism against PPA.…”

A Review: Biological and Technological Functions of Barley Seed Pathogenesis-Related Proteins (PRs)

“…Baker's asthma, a typical occupational allergic disease 31 provoked by flour proteins, is caused by CMs 19 . The high inhibitory activity of some cereal seed CMs against porcine pancreas α-amylase, together with high thermal stability, suggests potential for use in prevention and therapy of obesity and diabetes 244 .…”

AnIn VitroandIn VivoStudy of the α-Amylase Activity of Phaseolamin

“…This type of inhibitor can be used to treat type 2 diabetes mellitus and obesity. [3][4][5][6] Phaseolamin is a glycoprotein that was characterized in 1975, is present in white beans and kidney beans (Phaseolus vulgaris), and contains an a-amylase inhibitor termed a-AI. 7 Moreover, phaseolamin is used as a dietary supplement and is present in pharmaceutical products marketed as protein concentrates for weight management.…”