Table 1 Effect of protease inhibitors, organic solvents, metal ions, and detergents on the activity of the keratinolytic extracts obtained with Bacillus cytotoxicus LT-1 and Bacillus cytotoxicus Oll-15. Each determination was performed in triplicate. Residual activity is expressed as a percentage, comparing with the activity measured in the absence of any compound. Asterisks show the differences with a P < 0.05 (LSD test, ANOVA).

  PMSF

1 mM

87.8 ± 3.0*

95.8 ± 4.4*

  Iodoacetamide

1 mM

89.7 ± 4.2*

56.9 ± 3.2*

  EDTA

1 mM

4.5 ± 1.9*

0.6 ± 0.1*

  Phenantroline

1 mM

1.8 ± 0.5*

0.8 ± 0.5*

  Pepstatin A

5 μM

98.5 ± 1.2

111.1 ± 0.4*

  Mg⁺²

1 mM

121.8 ± 2.2*

130.1 ± 2.9*

  Zn⁺²

1 mM

107.5 ± 5.3*

112.2 ± 10.0*

  Ca⁺²

1 mM

143.8 ± 2.3*

147.2 ± 0.8*

  Mn⁺²

1 mM

117.5 ± 3.1*

116.2 ± 13.8*

  Co⁺²

1 mM

41.3 ± 4.4*

46.4 ± 3.3*

  Na⁺

1 mM

94.9 ± 6.7

82.7 ± 6.5*

  K⁺

1 mM

89.1 ± 4.2*

107.1 ± 6.4

  Hg⁺²

1 mM

28.5 ± 3.1*

27.9 ± 2.3*

  Methanol

1% v/v

98.3 ± 1.5

102.6 ± 1.7

  Ethanol

1% v/v

87.4 ± 3.7*

97.8 ± 2.7

  Isopropanol

1% v/v

84.9 ± 0.7*

87.3 ± 1.2*

  Ala

1% v/v

45.3 ± 3.2*

9.0 ± 1.1*

  Ariel

1% v/v

15.9 ± 1.4*

17.8 ± 6.6*

  Ace

1% v/v^-

42.3 ± 2.1*

1.9 ± 1.5*

  Skip

1% v/v

20.1 ± 1.1*

1.2 ± 2.1*

  Drive

7 mg·l^-1

9.3 ± 1.5*

5.0 ± 1.5*

  Ariel

7 mg·l^-1

4.1 ± 1.2*

2.0 ± 0.7*

  Ace

7 mg·l^-1

10.7 ± 1.4*

39.1 ± 1.5*

  Skip

7 mg·l^-1

4.7 ± 1.3*

2.1 ± 0.6*