| Project/Area Number |
60570873
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Functional basic dentistry
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| Research Institution | Okayama University |
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Principal Investigator |
TAKAHASHI Kojiro Okayama University Dental School, 歯学部, 助手 (00144775)
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| Co-Investigator(Kenkyū-buntansha) |
TANIGUCHI Shigehiko Okayama University Dental School, 歯学部, 教授 (50034161)
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| Project Period (FY) |
1985 – 1986
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| Project Status |
Completed (Fiscal Year 1986)
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| Budget Amount *help |
¥1,700,000 (Direct Cost: ¥1,700,000)
Fiscal Year 1986: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1985: ¥1,400,000 (Direct Cost: ¥1,400,000)
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| Keywords | Alkaline phosphatase / Allosteric effect / Cooperativity / Enzyme intermediate / Phosphoamino acids / NMR / Phosphotyrosine specificity |
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| Research Abstract |
The activity of calf bone alkaline phosphatase (AlP) was regulated with temperature and pH. At the temperature above 32-35 ゜C, the substrate saturation curve was a Michaelis type at pH 10.5 or a substrate inhibition type at pH 7.5. Below 32-35 ゜C, on the other hand, the possitive and negative cooperativities were observed at pH 10.5 and 7.5, respectively.
The reexamination of AlP activity for phosphoamino acids (P-Tyr, P-Ser and P-Thr) with <^(31)P> NMR spectroscopy indicated: (1) in the one-substrate system, the initial velocity of dephosphorylation was identical among three phosphoamino acids, but the velocity with P-Tyr after the steady state was higher than those with P-Ser and P-Thr; (2) in the two-substrate system, both of the initial and post-steady state velocities with P-Tyr were higher than those with P-Ser and P-Thr; and (3) alcoholic hydroxyl group in Ser or Thr as the dephosphorylation product was rephosphorylated by the transphosphorylase action of AlP. These facts implies that the physiological function of the enzyme in vivo may be the regulation of phosphate concentration in hard tissues with the transphosphorylation action.
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