人血清中糖基磷脂酰肌醇－特异性磷脂酶D活性的测定

我们用含糖基磷酯酰肌醇疏水膜锚结构（ＧＰＩ－ａｎｃｈｏｒ）的碱性磷酸酶（ＡＬＰ）作为底物，建立了稳定可靠的测定血清中ＧＰＩ专一的磷酯酶Ｄ（ＧＰＩ－ＰＬＤ）活性的条件，活性用ＡＬＰ由疏水性到亲水性的转化率（％）表示。经测定，健康人群的活性水平在转化率为２０～６０％之间者占９５％以上，低于２０％者仅占０．９％。在普查了多种疾病患者血清的酶活性的基础上，统计了几种疾病患者血清的酶活，其中肾衰、肠癌、肝癌、肝硬化以及甲型和乙型肝炎病人血清的酶活有所下降，活性低于２０％者较正常人高１５至４０倍，而急性肝炎恢复期的病人，酶活水平恢复正常。另外发现，高血脂患者的酶活性则明显高于对照值。造成血清中ＧＰＩ－ＰＬＤ活性水平改变的原因尚不清楚，但可能不是由单一器官功能不全所致。

Determination of Glycosylphosphatidylinositol-specific Phospholipase D Activity in Human Serum

e measured serurn glycosylphosphatidylinositol-specific phospholipase D(GPI-PLD) by itsalkaline phosphatase conversion rate. The assay is reliable and sufficiently precise for routine use.Above 95%of healthy individuals,the activity level of GPI-PLD in the serum are between 20%and 60%of ALP conversion rate,but they are considerably low in patients with liver disease,aswell as renal and intestinal disease. The amount of patients with conversion rate below 20%is 15to 40 fold higher than that of healthy group.We also found that the activity level was significant-ly higher in the patients with high blood lipid than healthy group.The reason causing differenceof enzyme activity between healthy and diseased group remains unknown,It seems not to be theresult of function failure of individual organ.