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Soybean P34 Probable Thiol Protease Probably Has Proteolytic Activity on Oleosins
Luping Zhao1, Xiangzhen Kong1, Caimeng Zhang1
1State Key Laboratory of Food Science and Technology, Jiangnan University, School of Food Science and Technology, Jiangnan University , 1800 Lihu Avenue, Wuxi, Jiangsu Province 214122, P. R. China.
Journal of Agricultural and Food Chemistry
|June 29, 2017
Summary
Soybean thiol protease P32, identified as a probable thiol protease, specifically cleaves 24 kDa oleosin. This protease, P32, forms complexes with oil bodies and hydrolyzes oleosin into smaller fragments.
Area of Science:
- Biochemistry
- Plant Science
- Proteomics
Background:
- Soybean oil bodies contain 24 kDa oleosin, a protein potentially processed by related proteases like P34 and Gly m Bd 30K.
- Bioprocessing of soybean can yield distinct protease forms, P32 (from P34) and 28K (from 30K).
Purpose of the Study:
- To characterize the proteolytic activity and substrate specificity of bioprocessed soybean thiol proteases, P32 and 28K.
- To investigate the interaction of P32 with soybean oil bodies and its role in oleosin hydrolysis.
Main Methods:
- Separation and purification of bioprocessed P34 (P32) and 30K (28K) from germinated soybean.
- Assay of proteolytic activity and cleavage site specificity of P32 and 28K.
- Incubation of P32 with purified soybean oil bodies and analysis of resulting complexes and hydrolysis products.
Main Results:
- P32 exists as a dimer and exhibits high proteolytic activity and cleavage specificity for Lys-Thr in 24 kDa oleosin, while 28K exists as a monomer with low activity.
- P32 dimers dissociate upon binding to oil bodies, forming complexes with 24 kDa oleosins.
- Hydrolysis of 24 kDa oleosin by P32 yields 17 kDa and 7 kDa fragments, with P32 also binding to the 17 kDa fragment.
Conclusions:
- P32 is identified as the primary thiol protease responsible for the hydrolysis of 24 kDa oleosin in soybean oil bodies.
- The study elucidates the mechanism of P32-mediated oleosin degradation and its interaction with oil body components.
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