Loridan C, Alouf J E
J Gen Microbiol. 1986 Feb;132(2):307-15. doi: 10.1099/00221287-132-2-307.
RNA-core (RNAase-resistant fraction of yeast RNA) induced streptolysin S (SLS) was purified (40% recovery) to apparent electrophoretic homogeneity by hydroxylapatite chromatography followed by gel filtration on Sephadex G-100 in the presence of 6 M-guanidine. HCl. The specific activity of the purified toxin was 3 X 10(6) haemolytic units (mg protein)-1. The Mr of the toxin was below 4000 on the basis of SDS-PAGE and 20 000 by gel filtration in guanidine. HCl. High-voltage isoelectric focusing of the purified toxin allowed the isolation of the carrier-free SLS peptide for the first time. This peptide was basic (pI 9.2) as compared to native SLS (pI 3.6). The native toxin and the peptide had similar haemolytic properties except for the high lability of the peptide, which was stabilized by RNA-core. The Mr of the denatured peptide was about 1800, as estimated by gel filtration.
RNA核心（酵母RNA的抗核糖核酸酶部分）诱导的链球菌溶血素S（SLS）通过羟基磷灰石色谱法进行纯化（回收率为40%），随后在6M盐酸胍存在的条件下，在Sephadex G - 100上进行凝胶过滤，达到表观电泳均一性。纯化毒素的比活性为3×10⁶溶血单位（毫克蛋白）⁻¹。基于SDS - PAGE，毒素的分子量低于4000，而在盐酸胍中通过凝胶过滤法测得的分子量为20000。对纯化毒素进行高压等电聚焦首次分离出了无载体的SLS肽。与天然SLS（pI 3.6）相比，该肽呈碱性（pI 9.2）。除了肽的高不稳定性（可被RNA核心稳定）外，天然毒素和该肽具有相似的溶血特性。通过凝胶过滤估计，变性肽的分子量约为1800。
