Park Chul, Novak John T, Helm Richard F, Ahn Young-Ock, Esen Asim
Department of Civil and Environmental Engineering, University of Massachusetts, Amherst, MA 01003, USA.
Water Res. 2008 Aug;42(14):3879-89. doi: 10.1016/j.watres.2008.05.014. Epub 2008 Jun 21.
The proteins present in the extracellular polymeric substances (EPS) of activated sludge flocs were investigated using three cation-associated extraction methods. The subproteomes generated from four full-scale activated sludges were subsequently fractionated by ammonium sulfate precipitation and analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The results showed that each extraction method led to unique SDS-PAGE protein profiles, which provided strong evidence that the extracted proteins are uniquely associated with specific cations in activated sludge flocs. The comparison of protein profiles across sludges from different treatment plants revealed that extracts obtained using a cation-exchange resin exhibited similar protein banding patterns while sulfide- and base-extracted EPS led to more variable protein profiles. Analysis of several SDS-PAGE bands by liquid chromatography-tandem mass spectrometry of tryptic digests led to the identification of several bacterial proteins as well as sewage-derived polypeptides (human elastase IIIA and keratins). Their putative roles in activated sludges and their association with targeted cations are proposed.
使用三种阳离子相关提取方法对活性污泥絮体胞外聚合物（EPS）中的蛋白质进行了研究。随后，通过硫酸铵沉淀对来自四个全尺寸活性污泥的亚蛋白质组进行分级分离，并通过十二烷基硫酸钠聚丙烯酰胺凝胶电泳（SDS-PAGE）进行分析。结果表明，每种提取方法都产生了独特的SDS-PAGE蛋白质谱，这有力地证明了所提取的蛋白质与活性污泥絮体中的特定阳离子具有独特的关联。对来自不同处理厂的污泥的蛋白质谱进行比较发现，使用阳离子交换树脂获得的提取物表现出相似的蛋白条带模式，而硫化物和碱提取的EPS导致更具变异性的蛋白质谱。通过对胰蛋白酶消化产物进行液相色谱-串联质谱分析，对几个SDS-PAGE条带进行分析，从而鉴定出几种细菌蛋白以及污水衍生的多肽（人弹性蛋白酶IIIA和角蛋白）。提出了它们在活性污泥中的假定作用及其与目标阳离子的关联。
