Fig 7. Stability of purified rhLY and hLY under different pH conditions.

The lysozyme was incubated in phosphate buffer of different pH values (from 2–12) for 20 minutes. Then the antibacterial activity against M. lysodeikticus was measured in phosphate buffered saline (pH 7.18) at room temperature. The lysozyme activity incubated in phosphate buffer at pH 7 was defined as 100% activity. hLY, commercial hLY; rhLY, purified rhLY. The experiment for each group was repeated at least three times, and the results were presented as mean ± S.D.