TABLE 3.

Dissociation constants of pyruvate and oxalate in HpaI aldolase determined by protein fluorescence quenching titration

All measurements were performed in 100 mm sodium HEPES buffer, pH 8.0.

Enzymes	Kd
	Pyruvate	Pyruvate and 0.5 mm Co2+	Oxalate and 0.5 mm Co2+
	mm	mm	μm
ApoHpaI	21.2 ± 2.4	0.32 ± 0.022	10.4 ± 0.75
ApoR70K	18.8 ± 1.3	0.32 ± 0.004	8.2 ± 0.3
ApoR70A	26.9 ± 3.1	0.47 ± 0.001	7601 ± 552
ApoD42A	32.5 ± 1.7	31.2 ± 1.6	a

^a No fluorescence quenching was observed for sodium oxalate at concentrations up to 40 mm.