Haendler B, Becker A, Noeske-Jungblut C, Krätzschmar J, Donner P, Schleuning W D
Research Laboratories, Schering AG, Berlin, Germany.
Blood Coagul Fibrinolysis. 1996 Mar;7(2):183-6. doi: 10.1097/00001721-199603000-00018.
Pallidipin is a platelet aggregation inhibitor protein originating from the saliva of the haematophageous triatomine bug Triatoma pallidipennis. Its inhibitory effects are specific for collagen-induced platelet aggregation. The recombinant form of the protein was expressed in the periplasmic space of transformed Escherichia coli using a vector based on the alkaline phosphatase gene promoter and leader peptide. Recombinant pallidipin was purified in three chromatographic steps including cation exchange, anion exchange and size exclusion gel chromatography. SDS/PAGE and N-terminal amino acid sequencing showed that recombinant pallidipin had a molecular weight similar to that of the salivary protein (approximately 19 kDa) and had been correctly processed. The yield was 864 micrograms of pure protein from one litre of bacterial culture. The biological activity of recombinant pallidipin was assessed in a platelet aggregation assay using collagen at a concentration of 2 micrograms/ml as inducer, and the IC50 found to be 33 nM, similar to that determined for the native protein. When the collagen concentration used for induction was increased, higher pallidipin concentrations were also needed to achieve a comparable inhibition of platelet aggregation.
苍白隐翅虫素是一种血小板聚集抑制蛋白，源自吸血的锥蝽Triatoma pallidipennis的唾液。其抑制作用对胶原诱导的血小板聚集具有特异性。该蛋白的重组形式利用基于碱性磷酸酶基因启动子和前导肽的载体在转化的大肠杆菌周质空间中表达。重组苍白隐翅虫素通过阳离子交换、阴离子交换和尺寸排阻凝胶色谱三个色谱步骤进行纯化。SDS/PAGE和N端氨基酸测序表明，重组苍白隐翅虫素的分子量与唾液蛋白相似（约19 kDa），且已正确加工。每升细菌培养物可产生864微克纯蛋白。在血小板聚集试验中，以浓度为2微克/毫升的胶原作为诱导剂评估重组苍白隐翅虫素的生物活性，发现其IC50为33 nM，与天然蛋白的测定值相似。当用于诱导的胶原浓度增加时，也需要更高浓度的苍白隐翅虫素来实现对血小板聚集的类似抑制。
