TABLE 2.

Activities of SaRha78A wild type and mutants for PNP-α-l-Rha

Enzyme	Substrate	CaCl2a	Km	kcat	kcat/Km
			mm	s−1	mm−1 s−1
WT	PNP-α-l-Rha	−	0.026 ± 0.003	26.4 ± 1.7	1014
WT	PNP-α-l-Rha	+	0.024 ± 0.002	27.2 ± 1.2	1115
WT	Gum arabic	+	238 ± 61b	0.003 ± 0.001	1.4 × 10−5 ± 7 × 10−6c
E636D	PNP-α-l-Rha	−	0.015 ± 0.002	0.07 ± 0.004	4.66
E636Q	PNP-α-l-Rha	−	0.22 ± 0.03	2.49 ± 0.18	11.3
E895D	PNP-α-l-Rha	−	0.022 ± 0.002	0.54 ± 0.20	24.5
E895Q	PNP-α-l-Rha	−	0.012 ± 0.003	0.29 ± 0.13	24.9
D179A	PNP-α-l-Rha	+	0.028 ± 0.002	27.5 ± 1.3	975
D179A	Gum arabic	+	NDd	ND	2.7 × 10−7 ± 4 × 10−9c
N180A	PNP-α-l-Rha	+	0.026 ± 0.004	24.4 ± 0.78	939
N180A	Gum arabic	+	ND	ND	2.7 × 10−7 ± 2 × 10−8c

^a Reaction mixture contained final 2 mm CaCl₂ indicated as +.

^b The number is given in mg/ml.

^c The numbers are given in mg/ml⁻¹s⁻¹.

^d Not determined as K_m was too high to measure.