TABLE 1.

Effects of divalent cations on His₆-BCTD GTPase and ATPase activities^a

Cation	% Activity (mean ± SE; n = 6)
	GTPase	ATPase
None	0	0
Mg2+	100	100
Mn2+	165 ± 14.5	125 ± 9.8
Ca2+	0	0
Zn2+	0	0
Co2+	15 ± 1.8	20 ± 2.8

^aGTPase and ATPase activities were measured with a nucleotide concentration of 10 μM as described in Materials and Methods; cations (5 mM) in their chloride form were used. Activities are standardized to that of the reaction mixture containing Mg²⁺.