Vinazzer H
Haemostasis. 1977;6(5):283-93. doi: 10.1159/000214193.
A photometric assay procedure for platelet factor 4 is described. The synthetic oligopeptide benzoyl-Ile-Glu-Gly-Arg-p-nitroanilide (S-2222) is used as a substrate. By the action of factor Xa, p-nitroaniline (pNA) is split form the peptide bond. The amount of pNA liberated from S-2222 per minute is in direct relation to the activity of factor Xa. This reaction permits a photometric assay. Addition of heparin to an activation system consisting of plasma, thromboplastin and calcium chloride inhibits development of Xa activity. Since platelet factor 4 neutralizes heparin, its activity can be measured in such a system when all other components are kept at a constant level. Experimental details of the reactions involved and clinical results of the assay in comparison to a clotting method are described.
本文描述了一种用于检测血小板第4因子的光度测定法。合成寡肽苯甲酰 - 异亮氨酸 - 谷氨酸 - 甘氨酸 - 精氨酸 - 对硝基苯胺（S - 2222）用作底物。在因子Xa的作用下，对硝基苯胺（pNA）从肽键上裂解下来。每分钟从S - 2222释放的pNA量与因子Xa的活性直接相关。该反应可进行光度测定。向由血浆、凝血活酶和氯化钙组成的激活系统中添加肝素会抑制Xa活性的产生。由于血小板第4因子可中和肝素，当所有其他成分保持恒定水平时，其活性可在这样的系统中进行测定。文中描述了所涉及反应的实验细节以及与凝血法相比该测定法的临床结果。
