Partial characterization of alpha-amylase in the salivary glands of Lygus hesperus and L. lineolaris.
The alpha-amylases in the salivary glands of Lygus hesperus Knight and L. lineolaris (Palisot de Beauvois) were isolated and purified by ion exchange chromatography, and by isoelectric focusing, respectively. The alpha-amylase from L. hesperus had an isoelectric point (pI) of 6.25, and a pH optimum of 6.5. The specific activity of alpha-amylases in the salivary glands of L. hesperus was 1.2 U/mg/ml. The alpha-amylase from L. lineolaris had a pI of 6.54, and a pH optimum of 6.5. The specific activity of alpha-amylase from L. lineolaris was 1.7 U/mg/ml. The activity of alpha-amylase in both species was significantly inhibited by alpha-amylase inhibitor from wheat and also by EDTA and SDS. Sodium chloride enhanced alpha-amylase activity for both species. The enzyme characteristics and relative activities are discussed in the context of differences phytophagous versus zoophagous habits in these two congeneric species.
Zeng
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Biological Control and Mass Rearing Research Unit, USDA/ARS, Mississippi State, MS 39762, USA. fzeng@bcmrru.msstate.edu
Cohen
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AC
D000818:Animals; D002852:Chromatography, Ion Exchange / Q000379:methods; D004492:Edetic Acid; D004789:Enzyme Activation; D020062:Heteroptera / Q000201:enzymology*; D006863:Hydrogen-Ion Concentration; D007525:Isoelectric Focusing / Q000379:methods; D012469:Salivary Glands / Q000201:enzymology; D012967:Sodium Dodecyl Sulfate; D000516:alpha-Amylases / Q000037:antagonists & inhibitors / Q000302:isolation & purification / Q000378:metabolism*
D012967:Sodium Dodecyl Sulfate; D004492:Edetic Acid; D000516:alpha-Amylases