Table 4.

Effect of organic solvents on Nk activity

Solvent	Remaining activity (%) at concentration (%) of
	10	30
Methanol	100 ± 10.86	99 ± 3.44
Ethanol	118 ± 1.85	97 ± 2.65
Isopropanol	110 ± 6.36	92 ± 1.32
1-Butanol	120 ± 6.89	124 ± 16.68
Acetonitrile	113 ± 7.15	60 ± 1.59
Acetone	124 ± 4.24	120 ± 5.83

0.6 μg of the Nk was incubated in 50 mM Na-phosphate buffer pH 8 at 30°C for 1 h in the presence of 10 or 30% (v/v) of different organic solvents. The Nk activity was measured with 1 mM Suc-AAPF-pNA as a substrate at pH 9 and 65°C.