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Table 2 Effect of various selective amino acid modifying agents on α-GalNAcase and α-galactosidase activities of starfish α-GalNAcase I and II

From: Chemical and structural characterization of α-N-acetylgalactosaminidase I and II from starfish, asterina amurensis

Modifying agent

Residual activity (%)

Modified amino acid

Name

Conc. (mM)

Ia

Ib

II

DFP

0

100.0

100.0

100.0

-

3

85.7 ± 1.10

86.9 ± 1.53

77.1 ± 1.96

6

38.5 ± 0.84

41.1 ± 0.96

33.8 ± 1.21

Serine

8

4.2 ± 0.35

4.9 ± 0.78

18.5 ± 0.45

10

0 ± 0.12

0 ± 0.49

3.5 ± 0.43

CNM-HCl

10

97.4 ± 0.99

93.4 ± 1.56

95.6 ± 1.76

Aspartate

30

37.9 ± 0.58

31.4 ± 2.43

36.0 ± 0.57

50

1.7 ± 0.32

1.7 ± 0.69

5.5 ± 0.48

60

0.4 ± 0.51

0.8 ± 0.65

2.2 ± 0.39

NBS

0.005

48.5 ± 0.79

75.9 ± 1.78

54.4 ± 2.01

Tryptophan

0.01

26.5 ± 0.65

52.4 ± 1.45

14.9 ± 0.97

0.02

10.0 ± 0.62

24.8 ± 1.09

7.6 ± 0.72

0.04

1.0 ± 0.87

2.8 ± 0.76

1.1 ± 0.23

  1. The residual activity was determined against pNP-α-GalNAc (for α-GalNAcase activity) and pNP-α-galactoside (for α-galactosidase activity) as substrate. (Ia) Residual α-GalNAcase activity of enzyme I; (Ib) residual α-galactosidase activity of enzyme I; (II) residual α-GalNAcase activity of enzyme II. Data are presented as mean ± MD (n = 3)