Purification and characterization of two alpha-amylase inhibitors from seeds of tepary bean (Phaseolus acutifolius A. Gray).
Two proteinaceous alpha-amylase inhibitors termed alphaAI-Pa1 and alphaAI-Pa2 were purified from seeds of a cultivated tepary bean (Phaseolus acutifolius A. Gray, cv. PI311897). The two inhibitors differed in their specificity towards alpha-amylases of insect pests such as bruchids, although neither showed any inhibitory activity against alpha-amylases of mammalian, bacterial or fungal origin. AlphaAI-Pa2 resembles two common bean inhibitors, alphaAI-1 and alphaAI-2, in several characteristics such as N-terminal amino acid sequences and oligomeric structure being composed of alpha and beta subunits. In contrast alphaAI-Pa1 is composed of a single glycopolypeptide with a molecular mass of 35 kDa, and its N-terminal amino acid sequence resembled that of seed lectins in tepary bean and common bean. The information on the two tepary bean alpha-amylase inhibitors may be useful not only for providing insight into critical structure for the specificity towards different alpha-amylase enzymes but also for enhancing insect resistance in crops.
Yamada
T
T
Graduate School of Agricultural Sciences, Nagoya University, Chikusa, Nagoya, 464-8601, Japan.
Hattori
K
K
Ishimoto
M
M
D000595:Amino Acid Sequence; D000818:Animals; D001419:Bacteria / Q000201:enzymology; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D005658:Fungi / Q000201:enzymology; D006020:Glycopeptides / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology; D007313:Insecta; D007700:Kinetics; D008322:Mammals; D027805:Phaseolus / Q000737:chemistry*; D021122:Protein Subunits; D012639:Seeds / Q000737:chemistry*; D012680:Sensitivity and Specificity; D000516:alpha-Amylases / Q000037:antagonists & inhibitors*
D004791:Enzyme Inhibitors; D006020:Glycopeptides; D021122:Protein Subunits; D000516:alpha-Amylases