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. Author manuscript; available in PMC: 2016 Apr 1.
Published in final edited form as: Insect Biochem Mol Biol. 2015 Feb 17;59:58–71. doi: 10.1016/j.ibmb.2015.02.005

Table 3.

Kinetic characterization of the ascorbate oxidase activity of MCO1 orthologs.

Ascorbate
modela kcat
(min-1)		 Khalf or Km
(mM)		 kcat/Km
(min-1 mM-1)
DmMCO1 isoforms
DmMCO1T AS 2,570 ± 315 0.29 ± 0.05 8,806
DmMCO1T[R454A] AS 1,480 ± 170 0.27 ± 0.05 5,516
AgMCO1 isoforms
AgMCO1T AS 916 ± 84 0.12 ± 0.02 7,559
AgMCO1T[R542S] MM 568 ± 43 0.20 ± 0.04 2,785
TcMCO1 isoforms
TcMCO1Ts AS 12,912 ± 492 0.32 ± 0.01 39,766
TcMCO1Tl AS 10,541 ± 504 0.42 ± 0.02 25,357
MsMCO1 isoforms
MsMCO1Ts AS 3,013 ± 497 0.62 ± 0.16 4,838
MsMCO1Tl AS 4,059 ± 889 0.77 ± 0.27 5,244
Insect laccases
AgMCO3 MM 148 ± 36 0.64 ± 0.26 233
TcLac2A activity too low to characterize
Fungal laccase
TvLac-α MM 29 ± 3.4 0.21 ± 0.06 135
Ascorbate oxidase
Curcubita AOb 40,920 ± 2,040 0.20 ± 0.03 204,600
Curcubita AO AS 21,264 ± 996 0.17 ± 0.01 127,558

Note: the kinetic constants reported are best-fit values with standard errors

a

AS = allosteric sigmoidal; MM = Michaelis-Menten