Isolation and identification of a plant lysozyme from Momordica charantia L

A plant lysozyme exhibiting antifungal activity and with a molecular mass of 20.1 kDa in SDS-polyacrylamide gel electrophoresis was isolated from Momordica charantia L using a procedure that involved aqueous extraction, vacuum freeze-drying of extraction, and ion exchange chromatography on high-performance liquid chromatography on Source Q and POROS 50 HS. Its N-terminal sequence was determined to be Q-L-C-E-L-A-A-C-M-K-R-H-G-L-D, showing relatively high homology (about 80%) with that of hen egg white lysozyme. Its pI was estimated to be 9.9. The lysozyme exhibited a pH optimum at pH 5.5 and a temperature optimum at 50 °C. Moreover, the lysozyme exerted an antifungal action toward Mucorracemosus and Rhizoctonia solani, in addition to an antibacterial action against Escherichia coli and Staphylococcus aureus. © 2011 Springer-Verlag.