Regulation of alkaline phosphatase and the relation with calcification in hard tissues.

碱性磷酸酶的调节及其与硬组织钙化的关系。

• 批准号: 60570873
• 负责人: TAKAHASHI Kojiro
• 金额: $ 1.09万
• 依托单位: Okayama University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1985
• 资助国家: 日本
• 起止时间: 1985 至 1986
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-60570873/
• 关键词: Alkaline phosphatase; Allosteric effect; Cooperativity; Enzyme intermediate; Phosphoamino acids; NMR; Phosphotyrosine specificity

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.

小牛骨碱性磷酸酶（AlP）的活性受温度和pH的调节，在32-35 ℃以上，底物饱和曲线为米氏型（pH10.5）或底物抑制型（pH7.5）。而在32-35 ℃以下，在pH10.5和7.5时，则分别观察到正和负的协同作用。（P-Tyr、P-Ser和P-Thr）与<^（31）P> NMR光谱的比较表明：（1）在单底物体系中，三种磷酸化氨基酸的脱磷酸化初速度相同，（2）在双底物体系中，对-Tyr的初始和稳态后速率均高于对-Ser和对-Thr;（3）脱磷酸化产物Ser或Thr中的醇羟基在AlP的转磷酸酶作用下被再磷酸化。这些事实表明，该酶在体内的生理功能可能是通过转磷酸作用调节硬组织中磷酸盐浓度。

项目成果

Kojiro Takahashi: Journal of Biochemistry. 101(5). (1987)

高桥小次郎：生物化学杂志。

Kojiro TAKAHASHI: Kojiro TAKAHASHI: Kojiro TAKAHASHI: Kojiro TAKAHASHI: "Tyrosine-Specific Dephosphorylation-Phosphorylation with Alkaline Phosphatases and Epidermal Growth Factor Receptor Kinase as Evidenced by <^(31)P> NMR Spectroscopy." "Cooperativity

Kojiro TAKAHASHI：Kojiro TAKAHASHI：Kojiro TAKAHASHI：Kojiro TAKAHASHI：“通过 <^(31)P> NMR 光谱证明，用碱性磷酸酶和表皮生长因子受体激酶进行酪氨酸特异性去磷酸化-磷酸化。”