Table 4.

Kinetic parameters of purified DKGRsb

FormParameters
Km for DKGa(μM)kcat(s−1)kcat/Km (mM−1 s−1)Km for NADPH (μM)
A13,50040.313
B2,000391910
C57315503.0
D67274002.7
  • a DKG, 2,5-diketo-d-gluconic acid.

  • b Values for forms A and B are from Sonoyama and Kobayashi (35). For forms C and D, kinetic parameters for 2,5-diketo-d-gluconic acid were determined in the presence of 0.15 mM NADPH, and values for NADPH were determined in the presence of 1 mM 2,5-diketo-d-gluconic acid.