title: New protease inhibitors from buckwheat seeds: properties, partial amino acid sequences and possible biological role.
abstract: Preparations of new low molecular weight protein inhibitors of serine proteinases have been obtained from buckwheat Fagopyrum esculentum seeds by chromatography of seed extracts on trypsin-Sepharose 4B, Mono-Q and Mono-S ion-exchangers. Their molecular masses, determined by mass spectrometry, were equal to 5203 (BWI-1c), 5347 (BWI-2c), 7760 (BWI-3c) and 6031 daltons (BWI-4c). All inhibitors possessed high pH-stability in the pH range 2-12 and thermostability. In addition to trypsin, BWI-3c and BWI-4c inhibitors inhibited chymotrypsin and subtilisin-like proteases. The inhibition constants (Ki) for trypsin, chymotrypsin and subtilisin by the studied inhibitors were determined. The N-terminal sequences of all inhibitors were established: BWI-1c (23 residues), BWI-2c (33 residues), BWI-3c (18 residues) and BWI-4c (20 residues). According to the physicochemical properties and N-terminal amino acid sequences, buckwheat seed protease inhibitors BWI-3c and BWI-4c are suggested to belong to the potato proteinase inhibitor I family.
authors.affiliation: A.N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow 119992, Russia.
authors.forename: Tatiana
authors.initials: T
authors.lastname: Tsybina
authors.forename: Yakov
authors.initials: Y
authors.lastname: Dunaevsky
authors.forename: Alexander
authors.initials: A
authors.lastname: Musolyamov
authors.forename: Tsezi
authors.initials: T
authors.lastname: Egorov
authors.forename: Natalia
authors.initials: N
authors.lastname: Larionova
authors.forename: Natalia
authors.initials: N
authors.lastname: Popykina
authors.forename: Mikhail
authors.initials: M
authors.lastname: Belozersky
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D019612:Fagopyrum / Q000737:chemistry* / Q000201:enzymology; D007700:Kinetics; D008969:Molecular Sequence Data; D010447:Peptide Hydrolases / Q000378:metabolism; D011480:Protease Inhibitors / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology; D012639:Seeds / Q000737:chemistry / Q000201:enzymology
chemical_list: D011480:Protease Inhibitors; D010447:Peptide Hydrolases