Glycochenodeoxycholic acid inhibits calcium phosphate precipitation in vitro by preventing the transformation of amorphous calcium phosphate to calcium hydroxyapatite.
Glycochenodeoxycholic acid inhibits calcium phosphate precipitation in vitro by preventing the transformation of amorphous calcium phosphate to calcium hydroxyapatite.
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甘氨鹅去氧胆酸通过阻止无定形磷酸钙转化为羟基磷灰石钙来抑制体外磷酸钙沉淀。
DOI：
10.1172/jci115430
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发表时间：
1991
期刊：
影响因子：
--
通讯作者：
Crowther,RS
中科院分区：
文献类型：
--
作者：
Qiu,SM;Wen,G;Hirakawa,N;Soloway,RD;Hong,NK;Crowther,RS
羟基磷灰石钙是胆色素结石的重要成分。结合磷酸钙的不同分子抑制羟基磷灰石沉淀。因为甘氨酸结合胆汁酸，而不是其牛磺酸对应物，结合磷酸钙，我们研究了甘氨鹅去氧胆酸是否抑制羟基磷灰石钙的形成。甘氨鹅去氧胆酸（2 mM）完全抑制无定形磷酸钙微沉淀转化为宏观结晶羟基磷灰石钙。这种抑制作用不是由Ca 2+活性降低介导的。牛磺胆酸（2-12 mM）不影响羟基磷灰石的形成，但拮抗甘氨鹅去氧胆酸。无定形和结晶沉淀物都含有相对丰富的磷酸盐的表面分数。随着甘氨鹅去氧胆酸浓度的增加，表面磷酸盐含量逐渐减少，这种关系被解释为胆汁酸和HPO 4（-4）竞争磷酸钙表面的结合位点。一个磷酸盐丰富的晶体表面与快速从非晶态到晶态的过渡。这些结果表明，甘氨鹅去氧胆酸通过竞争性抑制磷酸盐在晶胚表面上的积累来防止无定形磷酸钙向结晶羟基磷灰石的转化。
Calcium hydroxyapatite can be a significant component of black pigment gallstones. Diverse molecules that bind calcium phosphate inhibit hydroxyapatite precipitation. Because glycine-conjugated bile acids, but not their taurine counterparts, bind calcium phosphate, we studied whether glycochenodeoxycholic acid inhibits calcium hydroxyapatite formation. Glycochenodeoxycholic acid (2 mM) totally inhibited transformation of amorphous calcium phosphate microprecipitates to macroscopic crystalline calcium hydroxyapatite. This inhibition was not mediated by decreased Ca2+ activity. Taurocholic acid (2-12 mM) did not affect hydroxyapatite formation, but antagonized glycochenodeoxycholic acid. Both amorphous and crystalline precipitates contained a surface fraction relatively rich in phosphate. The surface phosphate content was diminish by increasing glycochenodeoxycholic acid concentrations, and this relationship was interpreted as competition between bile acid and HPO4(-4) for binding sites on the calcium phosphate surface. A phosphate-rich crystal surface was associated with rapid transition from amorphous to crystalline states. These results indicate that glycochenodeoxycholic acid prevents transformation of amorphous calcium phosphate to crystalline hydroxyapatite by competitively inhibiting the accumulation of phosphate on the crystal embryo surface.