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Table 1 Specific hydrolyzing activity of chitinase A and mutants. The reducing sugar assay was carried out against crystalline and colloidal chitin. The release of the hydrolytic products was calculated from a standard curve of [GlcNAc]2. On the other hand, the specific hydrolyzing activity against p NP-[GlcNAc]2 was determined by the colorimetric assay. The release of p NP was estimated from a standard curve of p NP

From: The effects of the surface-exposed residues on the binding and hydrolytic activities of Vibrio carchariae chitinase A

Protein

Specific hydrolyzing activity (U/μmol protein)a

 

Crystalline chitin

Colloidal chitin

p NP-[GlcNAc]2

Wild-type

0.59 ± 0.02(100)b

12.9 ± 0.22 (100)

50.5 ± 1.13 (100)

S33A

n.d.c

8.5 ± 0.50 (66)

58.0 ± 1.08 (115)

S33W

1.00 ± 0.08 (166)

15.3 ± 0.32 (119)

54.0 ± 2.55 (107)

W70A

n.d.

4.3 ± 0.17 (33)

52.8 ± 2.14 (105)

W231A

n.d.

6.6 ± 0.26 (51)

45.2 ± 2.00 (90)

W231F

n.d.

9.2 ± 0.49 (71)

54.3 ± 2.85 (108)

Y245W

1.49 ± 0.09 (250)

19.6 ± 0.53 (152)

53.6 ± 1.61 (106)

  1. a One unit of chitinase is defined as the amount of enzyme that releases 1 μmol of [GlcNAc]2 or 1 nmol of p NP per min at 37°C.
  2. b Values in parentheses represent relative specific hydrolyzing activities (%).
  3. c Non-detectable activity.