. Author manuscript; available in PMC: 2009 Dec 3.

Published in final edited form as: Biochemistry. 2008 Dec 2;47(48):12860–12868. doi: 10.1021/bi801718d

Table 2.

Reaction Rates of StAhpC With Various Iodoacetamide Derivatives and Hydroperoxides at pH7.

	Reaction rate with AhpC (min^-1)^a
Fluorescein iodoacetamide	0.67
Iodoacetanilide	0.031
Iodoacetamide	0.0035
Hydrogen peroxide	3130^b
Cumene hydroperoxide	2460^b

Prereduced AhpC (40 μM) was incubated in pH 7 buffer with 400 μM iodoacetamide, iodoacetanilide (IAAn), or fluorescein iodoacetamide. Rates of reaction with iodoacetamide and IAAn were determined by a subsequent thiol assay conducted at multiple time points, whereas modification by fluorescein iodoacetamide was assessed using a gel method to detect fluorescently-labeled protein as described in Methods.

The reaction rates of AhpC with hydrogen peroxide and cumene hydroperoxide were calculated from the previously determined steady state parameters, k_cat and K_m (1, 36).