Sourek J
Zentralbl Bakteriol Orig A. 1975;231(1-3):259-68.
In the course of its isolation and purification, bacterial endotoxin may be contaminated by some inorganic cations. The present study was concerned with Cu-2+ contamination of the lipopolysaccharide-protein complex (LPS) extracted from Shigella dysenteriae 1 S and R strains. The Cu-2+ contamination level of LPS prepared by Raynaud's method and partly purified through Sephadex G200 and Sepharose 4B was in the range of 1-5 mug Cu-2+/mg LPS. Crude Raynauds extract, similarly as LPS prepared by Westphal's method without subsequent purification, contained 0.02-0,1 mug Cu-2+/mg LPS. The linkage of Cu-2+ to LPS was relatively weak; the Cu-2+ content could be substantially reduced, viz. to 0.05-0.1 mug/mg, by dialysis against solutions of suitable complex-forming agents (EDTA, DL-alpha alanine). Neither a grossly augmented (up to 60 mug/mg) nor a lowered Cu-2+ concentration (0.02 mug/mg) had any appreciable influence on the toxicity or other biological properties of LPS. Attention is drawn to this ability of LPS to bind and again readily release a relatively large amount of Cu-2+ and the possibility that this ability is utilized by the bacterial cell in Cu-2+ transport through the cell membrane.
在细菌内毒素的分离和纯化过程中，可能会被一些无机阳离子污染。本研究关注从痢疾志贺氏菌1型S和R菌株中提取的脂多糖 - 蛋白质复合物（LPS）的铜离子污染情况。通过雷诺方法制备并经Sephadex G200和Sepharose 4B部分纯化的LPS的铜离子污染水平在1 - 5微克铜离子/毫克LPS范围内。未经后续纯化的雷诺粗提物，与通过韦斯特法制备的LPS类似，含有0.02 - 0.1微克铜离子/毫克LPS。铜离子与LPS的结合相对较弱；通过用合适的络合剂（EDTA、DL-α-丙氨酸）溶液进行透析，铜离子含量可大幅降低，即降至0.05 - 0.1微克/毫克。大幅增加（高达60微克/毫克）或降低（0.02微克/毫克）的铜离子浓度对LPS的毒性或其他生物学特性均无明显影响。需注意LPS具有结合并再次轻易释放相对大量铜离子的能力，以及细菌细胞可能利用这种能力通过细胞膜进行铜离子转运的可能性。
