抄録
Background : In food science, research on miscellaneous grain crops has focused primarily on their
components, with limited studies conducted on their germination. In this study, we isolated and
purified amylases from germinating seeds of various miscellaneous grain crops, including barnyard,
foxtail, and common millets, and examined their properties.
Methods : Amylase was extracted from germinated seeds from barnyard, foxtail, and common
millets and purified using ion exchange chromatography, chromatofocusing, and gel filtration
chromatography with Sephadex G-100. The enzyme properties, including pH and temperature
effects, molecular weight,isoelectric point, Km value, metal ion effects, and substrate specificity,
were then determined.
Results : Two types of amylase enzymes, amylases I and II, were purified from each germinated
seed. The purified amylases were identified as (sulfhydryl) SH enzymes because their activities
were inhibited by Hg2+, monoiodoacetic acid（MIA）, and p-chloromercuribenzoic acid (PCMB).
Based on the breakdown products, amylase I was classified as a β-amylase, effectively hydrolyzing
starch, amylopectin, and low-molecular-weight amylose. Amylase II, characterized by the
appearance of its breakdown products, was identified as an α-amylase, catalyzing the breakdown of
starch, amylopectin, and both low- and high-molecular-weight amyloses.
Conclusions : Clarifying the properties of amylases in the germinating seeds of miscellaneous grain
crops is important for understanding their potential applications and studying their germination
physiology.
