Table II.

Apparent nucleotide K_d for recombinant Rubisco activase as measured by various methods

Enzyme	ANSa				Intrinsicb		TNP-ATPc		ATPased
	Kd ADP	RWT	Kd ATP	RWT	Kd ATP	RWT	Kd	RWT	S0.5	RWT
	μm	%	μm	%	μm	%	μm	%	μm	%
43-kD RWT	0.77	–	8.8	–	10	–	0.07	–	13	–
Q111D	4.0	520	293.0	3,300	25	250	0.82	1,170	43	330
Q111E	2.6	340	64	730	4.5	45	0.10	140	11	80
Q111S	4.5	580	15	580	13	130	0.08	110	7	50

Assay conditions for the fluorescence methods are described in “Materials and Methods.” ATPase activity was measured by the coupled spectrophotometric method.

^a Calculated errors for all K_d values were less than ±10% except for the Q111D protein, which had an error of ±33%. 

^b Calculated errors for all K_d values were ±10% except for the Q111D protein which had an error of 16%. 

^c Calculated errors for the RWT, Q111D, Q111E, and Q111S proteins were ±: 0.01, 0.68, 0.09, and 0.03, respectively. 

^d Calculated errors for RWT, Q111D, Q111E, and Q111S proteins were ±: 16%, 30%, 23%, and 12%, respectively.