Table 2.

Steady-state kinetic constants for PAc hydrolase-catalyzed hydrolysis of PAc and various analogs at 25 °C and pH 7.0 (except where noted). See Materials and Methods for details.

Substrate	kcat (s−1)	Km (mM)	kcat/Km (M−1 s−1)
phosphonoacetatea	0.27 ± 0.1	0.060 ± 0.009	5 × 103
phosphonoacetatea (30 °C)	0.67 ± 0.1	0.015 ± 0.001	4 × 104
p-nitrophenylphosphateb	0.22 ± 0.1	14 ± 0.2	2 × 101
2-phosphoglyceratea,c	4 × 10−5	------	------
3-phosphoglycerola,c	4 × 10−5	------	------
p-nitrophenylsulfateb	~2 × 10−7	~ 10	~2 × 10−4
ATPa	2 ×10−4	1	2 × 10−1
phosphonopyruvatea	NAd	------	------
phosphonoacetaldehydea	0.027 ± 0.01	0.33 ± 0.01	8 × 101
fosfomycina,c	NAd	------	------
bis-p-nitrophenylphosphateb,c	NAd	------	------

^aThe reaction buffer was 50 mM K⁺ADA (pH 7.0).

^bThe reaction buffer was 50 mM K⁺TRICINE (pH 8.0).

^cTested at a concentration of 2 mM. For 2-phosphoglycerate and 3-phosphoglycerol the ratio of the initial velocity and the enzyme concentration is used to approximates the k_cat value.

^dNo activity (NA) was observed within the detection limit of ~ 1 × 10⁻⁷ s⁻¹.