A hypothesis as to mechanism of perturbation in biomembrane due to endotoxin. Participation of lysosomal cationic proteins with an endotoxin binding capacity

1)阳离子蛋白(CAP‘s)的分离：经0.1M柠檬酸提取、乙醇沉淀、凝胶过滤等步骤，从腹膜粒细胞中分离出阳离子蛋白。由于CAP能与肝素结合，因此正在研究用肝素琼脂糖纯化CAP。2)CAP能凝集脂多糖致敏的红细胞，尤其是Re-LPS(CAP-HA)；CAP与LPS预先孵育可抑制CAP-HA；3)CAP与LPS结合，尤其是水溶液中的Re-LPS，使浊度增加；浊度的增加取决于CAP的水平，尽管结合是以CAP和LPS的最佳比例发生的；低离子强度条件和pH 6-7对CAP-HA是最佳的；结合是可逆的。这似乎与CAP和内毒素的离子和疏水结合有关。4)CAP对S、R型革兰氏阴性菌和革兰氏阳性菌均有抗菌活性，其中对革兰氏阴性菌的抗菌活性最强。5)CAP与肝素结合使其混浊程度增加，相互中和了CAP和肝素的性质。6)相对分子质量小于10,000的一种CAP组分具有较高的抗凝血活性。7)CAP似乎能促进与红细胞等细胞结合的内毒素的活性和膜的扰动。

1) Fractionation of cationic proteins (CAP's); CAP's were fractionated from rebbit peritoneal granulocytes through the steps of 0.1 M citric acid extraction, ethanol precipitation and gel filtration by FPLC. Since CAP's were capable of binding with heparin, a purification using heparin Sepharose is being investigated.2) CAP's agglutinated the erythrocytes sensitized with LPS, especially Re-LPS (CAP-HA); CAP-HA was inhibited by preincubation of CAP with LPS.3) CAP bound with LPS, especially Re-LPS in water solution, and made increased turbidity; the increase of turbidity depended upon CAP-levels, although the binding took place at an optimal ratio of both CAP and LPS levels; Low ionic strength condition and pH 6-7 were optimal to CAP-HA; the binding was reversible. This seems to be involved in both ionic and hydrophobic bounds of CAP and LPS. CAP-HA is thought to result from the binding mentioned above.4) CAP exhibited antibacterial activity against S and R form gram-negative bacteria as well as gram-positive bacteria, expecially against R from gram-negatives. The activity seems to be bacteriolytic.5) CAP bound with heparin made increased trubidity, consequently the binding neutralized mutually the properties of CAP and heparin.6) One CAP fraction of less than 10,000 M.W. had high anticoagulant activity compared to other properties.7) It seems that CAP can promote the activity of LPS, which bound with cells such as erythrocytes, and membrane perturbation.