Fig. 2
The SDS-PAGE analysis of proteins and zymogram analysis of the lytic activity of Peptidase M15A against E. coli peptidoglycan. The Coomassie Brilliant blue stained SDS-PAGE gel shows protein molecular weight marker (M), induced E. coli cells containing pQE31 vector (lane 1), induced cells containing peptidase M15A/pQE31 plasmid (lane 2), 5 μg of purified peptidase M15A protein (lane 3) and the zymogram that is stained with 0.1 % methylene blue in 0.01 % KOH of SDS-PAGE refolding gel (lane 4). The clear lysis of PG substrate by the enzyme on zymogram located at the same position of the over-expressed protein band in lane 2 and purified enzyme in lane 3. The arrow indicates the 18 kDa lytic band of peptidase M15A