Table 1.

Catalytic constants of tyrosine phosphatase and phytase activity of XopH^a

Substrate	Additive	V max (µmol L−1 min−1)	K M (µM)	k cat (s−1)	k cat/K M (M−1 · s−1)	R 2
pTyr2	10 mM NaCl, 1 mM MgCl2	0.63 ± 0.16	25.7 ± 12.2	0.009	3.50 × 102	0.89
pTyr-chip	10 mM NaCl, 1 mM MgCl2	0.21 ± 0.12	29.7 ± 3.0	0.028	9.42 × 102	0.99
		(p mol µg −1 min −1 )
InsP6	100 mM NaCl, 1 mM MgCl2	40.0 ± 5.1	72.9 ± 13.7	19.4	2.66 × 105	0.99
InsP6	10 mM NaCl	110.6 ± 9.5	138.3 ± 15.0	45.3	3.28 × 105	0.99

^aActivity was measured in 50 mM HEPES (pH 7.0) under reducing conditions as described in “Methods” section