preliminary study of the protease activities in germinating brown rice (Oryza sativa L.)

BACKGROUND: Proteases hydrolyse storage proteins to provide precursors for perpetuating species. The aim of this study was to investigate and characterise different proteases in germinating brown rice. RESULTS: The protease activity of brown rice increased sevenfold during 7 days of germination. It...

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Bibliographic Details
Published in:Journal of the science of food and agriculture 2011-03, Vol.91 (5), p.915-920
Main Authors: Li, Cuijuan, Cao, Xiaohong, Gu, Zhenxin, Wen, Huanbin
Format: Article
Language:English
Subjects:
activity bands
Biological and medical sciences
brown rice
Caseins - metabolism
Cereal and baking product industries
Edible Grain - enzymology
Edible Grain - growth & development
Electrophoresis, Polyacrylamide Gel
Enzyme Inhibitors - metabolism
Enzyme kinetics
Food industries
Food science
Fundamental and applied biological sciences. Psychology
Germination
Germination - physiology
Hydrogen-Ion Concentration
Metalloproteases - metabolism
Oryza - enzymology
Oryza - growth & development
Peptide Hydrolases - metabolism
Plant Proteins - metabolism
protease
protease classes
Proteases
Rice
Studies
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Summary:BACKGROUND: Proteases hydrolyse storage proteins to provide precursors for perpetuating species. The aim of this study was to investigate and characterise different proteases in germinating brown rice. RESULTS: The protease activity of brown rice increased sevenfold during 7 days of germination. It was highest on day 6 when determined at pH 3.5. With casein as substrate the proteases showed two catalytic groups: acidic proteases with an optimal pH of 3.5 and alkaline proteases with an optimal pH of 8.0. The acidic protease activity was inhibited by Ba²⁺ and Pb²⁺ but stimulated by Zn²⁺, while the alkaline protease activity was inhibited by Ca²⁺ and Pb²⁺ but stimulated by Mg²⁺ and Zn²⁺. SDS-gelatin-PAGE assay showed two protease activity bands at pH 3.5, while two different bands with higher molecular weights were observed at pH 8.0. Inhibition assay revealed that pepstatin A and E-64 inhibited 67.63 and 38.26% respectively of the protease activity at pH 3.5, indicating the presence of aspartic and cysteine proteases. Metalloproteases played a major role under alkaline conditions (88.37% inhibition with EDTA). CONCLUSION: Germinated brown rice proteases fall into different classes with different properties. This study is helpful for their further purification. Copyright
ISSN:0022-5142
1097-0010
DOI:10.1002/jsfa.4265