Abstract
The complete amino acid sequence of protease inhibitor BWI-4a from buckwheat (Fagopyrum esculentum Moench) seeds, consisting of 67 amino acid residues with a single disulfide bond, has been established by Edman degradation in combination with matrix-assisted laser desorption ionization time-of-flight mass spectrometry. Its N terminus is blocked by a pyroglutamic acid residue. Mass spectrometric analysis revealed that inhibitor BWI-4a is present in buckwheat seeds in two isoforms with a single amino acid substitution of Ala40 for Gly40. The reactive site of the inhibitor contains an Arg43-Asp44 bond. Analysis of the amino acid sequence suggests that the buckwheat seed protease inhibitor is a member of the potato proteinase inhibitor I family.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Alanine / chemistry
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Amino Acid Sequence
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Binding Sites
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Chymotrypsin / metabolism
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Disulfides
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Fagopyrum / chemistry*
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Glycine / chemistry
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Leucine / chemistry
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Mass Spectrometry
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Molecular Sequence Data
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Peptides / chemistry
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Plant Proteins / chemistry*
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Protein Isoforms
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Pyrrolidonecarboxylic Acid / chemistry
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Sequence Homology, Amino Acid
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Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
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Trypsin / metabolism
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Trypsin Inhibitors / chemistry
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Trypsin Inhibitors / pharmacology
Substances
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Disulfides
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Peptides
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Plant Proteins
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Protein Isoforms
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Trypsin Inhibitors
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buckwheat inhibitor 4a
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proteinase inhibitor I (plants)
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Chymotrypsin
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Trypsin
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Leucine
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Alanine
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Pyrrolidonecarboxylic Acid
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Glycine