Table IV.

The Effect of Different Metal Ions on the Specific Activity of the Enzymes

	Specific activity (%)
	Before dialysis	No metals	Mg2+ Zn2+	Mg2+ Co2+	Mg2+	Zn2+	Co2+
wtTAP	100	1.2	64	24	70	4.4	1.5
H135D	100	18	98	76	89	70	21
H135E	100	1	78	7	16	17	1

All values were determined at 25°C in a buffer containing 1 M diethanolamine-Cl pH 10, 10% glycerol and 5 mM pNPP in the presence or absence of 1 mM MgCl₂, 1 mM ZnCl₂, and 1 mM CoCl₂ (as indicated). Reported values are the average of at least three measurements, and standard deviations do not exceed 5%.