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Table 1 Kinetic parameters of chitin oligosaccharide hydrolysis.

From: Novel β-N-acetylglucosaminidases from Vibrio harveyi 650: Cloning, expression, enzymatic properties, and subsite identification

Substrate

Km (μM)

kcat (s -1 )

kcat /Km (M -1 s -1 )

p NP-GlcNAc (Vh Nag1)

172 ± 48a

0.08

465

p NP-GlcNAc(Vh Nag2)

77 ± 17

0.38

4,935

GlcNAc2

179 ± 52

0.01

56

GlcNAc3

441 ± 98

0.10

228

GlcNAc4

329 ± 93

0.10

304

GlcNAc5

496 ± 78

0.09

181

GlcNAc6

421 ± 76

0.07

166

  1. a Results are means ± SD (n = 3 experiments for each substrate).
  2. The initial velocity of the reaction catalyzed by V. harveyi GlcNAcases was measured at 37°C, 10 min with varied concentrations of chitin oligosaccharides from 0-500 μM. The release of products was determined by the reducing sugar assay (see text). The kinetic experiments were carried out in triplicate. The kinetic parameters (Km, kcat, and kcat/Km) were estimated from a non-linear regression function available in GraphPad Prism v.5.0.