**4.5.1 Enzyme activity**

As shown in Table 5, the protease from different origin varied a lot in specific activity (W.J. Kim and S.M. Kim, 2005; Fu et al., 2008; Chung, 1984; Hwang et al., 2010). The specific activity of the *R. japonicus* protease II was the highest among these five proteases, and that of the *B. megaterium* KLP-98 was the lowest.


Table 5. Comparison of specific activities of purified salt-tolerant acid proteases.
