1998 Fiscal Year Final Research Report Summary
Studies on Transglutaminase Functioning as a Biomodulator Responsive to Food Environment
| Project/Area Number |
09660138
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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 | Kyoto Institute of Technology |
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Principal Investigator |
IKURA Koji Kyoto Institute of Technology, Applied Biology, Professor, 繊維学部, 教授 (00101246)
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| Project Period (FY) |
1997 – 1998
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| Keywords | transglutaminase / substrate proteins of transglutaminase / regulation of transglutaminase |
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| Research Abstract |
This study was done to understand the relationship between the food environment and the functions of protein cross-linking enzyme transglutaminase being involved in various biological phenomena. ofmammals. 1. To isolate the amine acceptor protein substrates of transglutaminase in mammalian livers, a biotin-labeled primary amine substrate of transglutaminase, biotincadaverine, was used forbiotin labeling of proteins in the liver extracts by endogenous transglutaminase activity. The biotin-labeled proteins were isolated and recovered by biotin-avidin-affinity chromatography The obtainedproteins were separated by SDS-PAGE and their amino-terminal sequences were determined. The 38-kDa protein from rat liver was identified as a subunit of glyceraldehyde-3-phosphate dehydragenase, and the 28 kDa protein from guinea pig liver was identified as a subunit of glutathione S-transferase (classtheta). The 44 kDa proteins from mouse, rat, and guinea pig livers were identified as betaine-homocysteine S-methyltransferase. Both the glyceraldehyde-3-phosphate dehydrogenase from rabbitmuscle and glutathione S-transferase (class pi) from human placenta also could be amine acceptors in the amine incorporation catalyzed by guinea pig liver transglutaminase. These results suggested that these identified enzyme proteins can be modified post-translationally by cellular transglutaminase. 2. lnsulin, which lowers the blood glucose level and is invoked in the regulations of cell growth and differentiation, was tested for its signaling effect on the transglutaminase activity of human hepatoblastoma HepG2 cells. Insulin did not affect significantly the transglutaminase activity of HepG2 cells cultured in both media with and without dexamethasone. Transglutaminase activity of HepG2 cells also did not respond to the treatments of insulin-like growth factors I and II, and glucagon.
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