Discontinuous polyacrylamide gel electrophoresis of cell wall proteinase from variants of Streptococcus lactis

An electrophoretic procedure has been developed for the separation of plasmid‐coded cell wall proteinases from Streptococcus lactis NCDO strain 712. The pH and casein concentration within the electrophoresis rod during detection is more closely defined than in existing methods. The incubation conditions used with casein, (approximately pH 7 and 30dEC) may be suitable for the detection of a wider range of proteinases from other sources. Four proteinase bands present in the cell wall have been detected in milk grown cells, but only two in those previously grown in a broth medium. No cell wall proteinases were detected in a proteinase deficient variant.