Pseudomonas aeruginosa Exopolyphosphatase Is Also a Polyphosphate: ADP Phosphotransferase

Table 4

Hydrolase and transferase activity of mutated variants of paPpx.

Ppx variant	Hydrolase		Transferase
	Specific activity^1	%	Specific activity^2	%
paPpx	1.49 ± 4E^−2	100	10.92 ± 4E^−1	100
N-paPpx	0.38 ± 6E^−3	25.5	1.34 ± 4E^−2	12.3
E126A^3	0.016 ± 5E^−5	1.1	0.21 ± 9E^−4	1.9
D149A^3	0.056 ± 7E^−5	3.8	0.31 ± 4E^−4	2.8
S154A^3	0.079 ± 1E^−4	5.3	0.46 ± 1E^−3	4.2
G151A^3	0.105 ± 4E^−4	7.1	0.69 ± 2E^−3	6.3
E156A^3	0.034 ± 2E^−4	2.3	0.23 ± 9E^−4	2.1

Values are means ± SD of at least three experiments performed independently. Both activities were measured with 8 μM polyP₆₅, 5 mM of Mg²⁺, and 80 mM of K⁺.
¹μmol of P_i min⁻¹μmol protein⁻¹.
²nmol of ATP min⁻¹μmol protein⁻¹.
³Mutated variants are all full-length paPpx.