Table 3.
Effect of ions on the activity of the new endo-β-1,4-xylanase

Metal ions (1 mM)	Relative enzyme activity (%)
Control	100
Cu+2	N.D.
Ca+2	226
Co+2	N.D.
K+	53
Ba+2	23
Fe+2	2
Zn+2	106
Mn+2	N.D.
Mg+2	N.D.
Fe3+	N.D.
Na+	21

N.D.: not detectable