SDS-polyacrylamide gel electrophoresis analysis of φ12 and φ11 endolysins and derived proteins purified by nickel-nitrilotriacetic acid affinity chromatography. The purified proteins were analyzed by 15% SDS-polyacrylamide gel electrophoresis and stained with PageBlue protein staining solution (Fermentas) according to the manufacturer's instructions. Lane M1, Fermentas Page Ruler unstained protein ladder; lanes M2, Fermentas prestained protein molecular weight marker; lane 1, φ12 endolysin (full length); lane 2, φ11 endolysin (full length); lane 3, φ11endo/ami; lane 4, φ11endo/CBD; lane 5, φ11ami/CBD; lane 6, φ11endo; lane 7, φ11ami.