Table II.

ATPase Activity of Wild-Type and Hybrid Enzymes

	Specific activity (μmol/min/mg) for production of ADP in the presence of various substratesa
Enzyme	ATP	ATP HCO3−	ATP AIR	ATP AIR HCO3−	ATP HCO2−	ATP GAR	ATP GAR HCO2−
PurT	0.021	0.031	0.033	0.030	0.16	4.64	5.14
PurK	0.23	1.09	8.72	10.0	0.35	0.46	0.40
KATBC	0.45	0.40	0.39	0.41	0.47	0.54	0.61
TAKBC	0.66	0.69	0.91	0.96	0.65	0.61	0.67
TACKB	0.073	0.073	0.087	0.13	0.061	0.10	0.099
KACTB	0.028	0.026	0.053	0.077	0.022	0.033	0.037
KABTC	0.16	0.15	0.14	0.14	0.14	0.10	0.12
TABKC	0.26	0.23	0.25	0.27	0.20	0.22	0.28

^aSpecific activities were determined by measuring ATPase activities under saturating concentrations of each substrate. The standard error for each value is less than 20%.