The phospholipase activity assays detected by TLC of various cell fractions prepared from wild type (wt) strain M93sm and plp mutant strain S262 (plp-) were performed at 37 ° C (A) and 64 ° C (B). PBS buffer, LB20, and PBS buffer + 1% sarcosylate were served as negative controls. The refolded rPlp protein (PLP +) served as positive control. The top spots on each chromatogram are the BPC substrate and the bottom spots are the BLPC reaction product. The proteins from the same cell fractionation preparations were analyzed by SDS-PAGE and Western blot analysis (C) as described in the Methods. The refolded rPlp protein was served as positive control.