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PURIFICATION AND CHARACTERIZATION OF AN α‐AMYLASE INHIBITOR FROM RYE (SECALE CEREALE) FLOUR
Author(s) -
GRANUM PER EINAR
Publication year - 1978
Publication title -
journal of food biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.507
H-Index - 47
eISSN - 1745-4514
pISSN - 0145-8884
DOI - 10.1111/j.1745-4514.1978.tb00607.x
Subject(s) - secale , amylase , isoelectric point , chromatography , chemistry , biochemistry , aspergillus oryzae , polyacrylamide gel electrophoresis , fractionation , trypsin inhibitor , size exclusion chromatography , bacillus subtilis , centrifugation , biology , enzyme , bacteria , trypsin , botany , genetics
An α‐amylase inhibitor from rye (Secale cereale) flour has been purified to homogeneity by extraction with 70% ethanol, ammonium sulfate fractionation and column chromatography on DEAE‐ and CM‐cellulose. The isoelectric point was pH 5.8, and the molecular weight 28,000 by polyacrylamide gel electrophoresis with different gel concentrations and 27,000 by sedimentation equilibrium centrifugation. Under denaturating conditions the molecular weight was about 14,000, indicating two subunits identical in size. The inhibitor was active towards human salivary and hog pancreatic α‐amylases but inactive towards Bacillus subtilis and Aspergillus oryzae α‐amylases. The pH optimum for the reaction between the rye inhibitor and human salivary α‐amylase was 6.0. The inhibitor did not change activity when exposed to pH 2 (0.01M HCl), but prolonged digestion by trypsin destroyed the inhibitor. The rye α‐amylase inhibitor lost about 80% of its activity after 10 min at 100°C.