| Project/Area Number |
16405025
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 海外学術 |
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| Research Field |
Applied biochemistry
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| Research Institution | HOKKAIDO UNIVERSITY |
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Principal Investigator |
KIMURA Atsuo Hokkaido Univ., Grad.School of Agr., Prof., 大学院・農学研究科, 教授 (90186312)
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| Co-Investigator(Kenkyū-buntansha) |
MORI Haruhide Hokkaido Univ., Grad.School of Agr., Asso.Prof., 大学院・農学研究科, 助教授 (80241363)
OKUYAMA Masayuki Hokkaido Univ., Grad.School of Agr., Assi.Prof., 大学院・農学研究科, 助手 (00344490)
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| Project Period (FY) |
2004 – 2005
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| Project Status |
Completed (Fiscal Year 2005)
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| Budget Amount *help |
¥8,300,000 (Direct Cost: ¥8,300,000)
Fiscal Year 2005: ¥5,000,000 (Direct Cost: ¥5,000,000)
Fiscal Year 2004: ¥3,300,000 (Direct Cost: ¥3,300,000)
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| Keywords | Asian honeybee / α-glucosidase / honey / 国際情報交換 / タイ:韓国 |
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| Research Abstract |
We have analyzed three sucrose-degrading isozymes (α-glucosidase I,II, and III) in European honeybees, since these enzymes exhibited the interesting activity to sucrose of high concentration. α-Glucosidase I was a unique allosteric enzyme to display negative cooperativity in extremely high sucrose concentration. α-Glucosidase II also exhibited the allosteric property of positive cooperativity. α-Glucosidase III was a Michaelis-Menten-type enzyme to be secreted to nectar (bees gathered from flower) and to contribute to the formation of honey. Purpose of this project is i)existence of allosteric α-glucosidase in Asian honeybees, ii)investigation of honey-forming mechanism, and iii)regulation in expression of three α-glucosidase isozymes.
Four kinds of honeybee species were investigated in this research. From typical Asian honeybees (living in Thailand, Korea and Japan), three isozymes were isolated by chromatographic method. One of them was an allosteric enzyme having similar properties t
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o European honeybee α-glucosidase I, allowing to molecular analysis of negative cooperativity. The second enzyme was α-glucosidase II-type isozyme. Enzyme in honey was also investigated, and showed similar to one of enzymes (α-glucosidase III-type isozyme). cDNAs of these three enzyme were cloned. It was found that the expression of three isozymes was regulated. In small honeybees living in Thailand, three α-glucosidases were also found, in which two α-glucosidases were isolated. Their properties investigated were almost identical to those of α-glucosidases I and II. Enzyme in honey was compared with adult bee enzymes. All honeybee species studied in this project contained allosteric enzyme. Asian honeybees were divided into two types : i)having three α-glucosidase isozymes and ii)having two α-glucosidase isozymes. Recently, we found that bumblebees also had two α-glucosidase isozymes. Further research will elucidate the interesting molecular mechanism of sucrose-degrading enzymes in flower bees. Less
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