Digestive α-amylases from Tecia solanivora larvae (Lepidoptera: Gelechiidae): response to pH, temperature and plant amylase inhibitors

• Published in: Bulletin of entomological research Vol. 98; no. 6; pp. 575 - 579
• Main Authors: Valencia-Jiménez, A., Arboleda V, J.W., López Ávila, A., Grossi-de-Sá, M.F.
• Format: Journal Article
• Language: English
• Published: Cambridge, UK Cambridge University Press 01.12.2008
• Subjects: alpha-amylase; alpha-Amylases - antagonists & inhibitors; alpha-Amylases - chemistry; alpha-Amylases - physiology; Amaranthus; amylase inhibitors; Animals; Biochemistry. Physiology. Immunology; Biological and medical sciences; chemical constituents of plants; digestive enzymes; enzyme activity; enzyme inhibition; enzyme inhibitors; Enzyme Inhibitors - chemistry; Enzyme Stability; Fundamental and applied biological sciences. Psychology; Gelechiidae; heat stability; Hydrogen-Ion Concentration; Insecta; Invertebrates; isoelectric point; Larva - enzymology; Moths - enzymology; Moths - growth & development; Phaseolus coccineus; Phaseolus vulgaris; Physiology. Development; Plant Proteins - chemistry; potato; Tecia solanivora; Temperature; α-Amylase; amylase inhibitors; α-Amylase; Tecia solanivora; potato; Temperature; Insecta; Environmental factor; Pest; Enzymatic activity; Dicotyledones; Angiospermae; pH; Gelechiidae; Solanaceae; Enzyme; Solanum tuberosum; Enzyme inhibitor; Digestion; Glycosylases; Larva; Vegetable crop; Arthropoda; Glycosidases; Lepidoptera; Hydrolases; Spermatophyta; Tuber plant; Invertebrata
• ISSN: 0007-4853; 1475-2670
• DOI: 10.1017/S0007485308005944

The biochemical properties of the digestive alpha-amylase from Tecia solanivora larvae, an important and invasive insect pest of potato (Solanum tuberosum), were studied. This insect has three major digestive α-amylases with isoelectric points 5.30, 5.70 and 5.98, respectively, which were separated using native and isoelectric focusing gels. The alpha-amylase activity has an optimum pH between 7.0 and 10.0 with a peak at pH 9.0. The enzymes are stable when heated to 50°C and were inhibited by proteinaceous inhibitors from Phaseolus coccineus (70% inhibition) and P. vulgaris cv. Radical (87% inhibition) at pH 6.0. The inhibitors present in an amaranth hybrid inhibited 80% of the activity at pH 9.0. The results show that the alpha-amylase inhibitor from amaranth seeds may be a better candidate to make genetically-modified potatoes resistant to this insect than inhibitors from common bean seeds.