1999 Fiscal Year Final Research Report Summary
Molecular Dissection and Application of an Enzyme-Inhibitor System with Special Reference to a Proteinase That Specifically Decomposes a Hardly Soluble Protein in Food Seeds.
| Project/Area Number |
10660118
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
食品科学・栄養科学
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| Research Institution | The University of Tokyo |
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Principal Investigator |
ABE Keiko Graduate School of Agricultural and life Sciences, The University of Tokyo, Professor, 大学院・農学生命科学研究科, 教授 (10151094)
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| Co-Investigator(Kenkyū-buntansha) |
MATSUMOTO Ichiro Graduate School of Agricultural and life Sciences, The University of Tokyo, Assistant Professor, 大学院・農学生命科学研究科, 助手 (00291328)
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| Project Period (FY) |
1998 – 1999
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| Keywords | wheat grains / cysteine proteinases / gliadain / cystatins / flour processing |
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| Research Abstract |
A recombinant enzyme was produced from gliadain we found as a new cysteine proteinase in wheat seeds. It actually decomposed, though in vitro, gliadin as a major wheat protein and was found to be involved in the proteolysis of the storage protein during germination. Next, we cloned wheat cystatins by screening with oryzacystatin cDNA as a probe. Three cDNA clones encoding cystatins were thus obtained and it was disclosed that all these cystatins belong to the so-called "phytocystatin" family. In the mean time, we produced a recombinant species of gliadain by fusion with glutathione S-transferase (GST). The resultant GST-progliadain elicited a proteolytic activity under a weakly acidic condition, which was strongly inhibited by a commercially available preparation of egg cystatin as well as by oryzacystatin.
The activity was also inhibited to a similar extent by two wheat cystatins we obtained recombinantly. All these results suggest the possibility that a system of the proteolysis with wheat cysteine proteinases and its regulation with wheat cystatins can be industrially applied to food processing for flour quality improvement.
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