New protease inhibitors from buckwheat seeds: properties, partial amino acid sequences and possible biological role.
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.
Tsybina
Tatiana
T
A.N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow 119992, Russia.
Dunaevsky
Yakov
Y
Musolyamov
Alexander
A
Egorov
Tsezi
T
Larionova
Natalia
N
Popykina
Natalia
N
Belozersky
Mikhail
M
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
D011480:Protease Inhibitors; D010447:Peptide Hydrolases