Table 2.

Effect of metal ions on α-amylase activity

Metals salt	Relative α-amylase activity at different metal salt concentrations
	1 mM	5 mM
Control (H2O)	1.00	1.00
Na+	0.88	0.72*
K+	0.89*	0.79*
Ca2+	1.05	1.14*
Mg2+	0.77*	0.76*
Fe2+	0.92	0.73*
Zn2+	0.74*	0.27*
Cu2+	0.46*	0.24*

*Significant difference on metal either positive or negative (p = < 0.05)