Table 2.

Effect of metal ions and EDTA on the XylRc activity

Additive	Relative activity (%)
	1.0 mmol L−1	5.0 mmol L−1
Control	100 ± 2.4	100 ± 2.4
K+	128.6 ± 2.9*	88.6 ± 6.7
Ca2+	122.9 ± 3.5*	104.8 ± 6.2
Mg2+	120.1 ± 5.6*	103.9 ± 1.8
NH4+	113.8 ± 6.5*	100.9 ± 2.3
Co2+	110.7 ± 6.8	91 ± 6.3
Li2+	107 ± 6.1	101 ± 0.2
Mn2	101.8 ± 7.1	112 ± 8.3
Sr2+	104 ± 4.2	87 ± 6.2
Zn2+	91.1 ± 3.6	86.0 ± 3.6
Al3+	54.9 ± 7,7*	45 ± 6.2*
Cu2+	100.6 ± 1.7	26.1 ± 3,4*
Fe3+	64.4 ± 2.2*	48.8 ± 4.9*
Fe2+	71.3 ± 9.8*	0*
Hg2+	0*	0*
EDTA	119.9 ± 3.8*	86.7 ± 4.5

Control Assay without addition of ions was considered as control (100%) corresponding 220 ± 6.0 U mg⁻¹

*Significantly different from control group (p < 0.05)