Inhibition of Sunn pest, Eurygaster integriceps, α-amylases by α-amylase inhibitors (T-αAI) from Triticale.
The effect of triticale α-amylases inhibitors on starch hydrolysis catalyzed by the Sunn pest, Eurygaster integriceps Puton (Hemiptera: Scutelleridae) midgut amylases was examined. Biochemical studgawies showed that inhibitors from Triticale (a hybrid of wheat and rye) had inhibitiory effects on E. integriceps α-amylases. The effects of the triticale α-amylase inhibitor (T-αAI) on α-amylase of E. integriceps showed a dose dependent manner of inhibition, e.g. less inhibition of enzyme activity (around 10%) with a lower dose (0.25 mg protein) and high inhibition of enzyme activity (around 80%) when a high dose of inhibitor was used (1.5 mg protein). The enzyme kinetic studies using Michaelis-Menten and Lineweaver-Burk equations showed the K(m) remained constant (0.58%) but the maximum velocity (V(max)) decreased in the presence of a crude extract of Triticale inhibitors, indicating mixed inhibition. The temperature giving 50% inactivation of enzyme (T(50)) during a 30-min incubation at pH 7.0 was 73° C. The maximum inhibitory activity was achieved at 35° C and pH 5.0. Gel assays showed the meaningful inhibition of E. integriceps α-amylases by various concentrations of Triticale inhibitors. Based on the data presented in this study, it could be said that the T-αAI has good inhibitory activity on E. integriceps gut α-amylase.
Insect Biochemistry & Molecular Biology Lab, Plant Protection Dep, Agricultural and Natural Resources Campus, University of Tehran, Karaj, Iran. mmehrabadi@ut.ac.ir
Mohammad
M
Mehrabadi
Ali R
AR
Bandani
Fatemeh
F
Saadati
D000818:Animals; D005591:Chemical Fractionation; D004305:Dose-Response Relationship, Drug; D002523:Edible Grain / Q000737:chemistry*; D004591:Electrophoresis, Polyacrylamide Gel; D020062:Heteroptera / Q000201:enzymology*; D006863:Hydrogen-Ion Concentration; D007492:Iran; D007700:Kinetics; D010936:Plant Extracts / Q000302:isolation & purification / Q000494:pharmacology*; D012639:Seeds / Q000737:chemistry*; D013696:Temperature; D000516:alpha-Amylases / Q000037:antagonists & inhibitors*
D010936:Plant Extracts; D000516:alpha-Amylases