TABLE 1.

Kinetic characterization of wild-type and G2A human HMGCLL1

Property	HMGCLL1		Recombinant human HMGCLa		Avian HMGCLb
	Wild-type	G2A	Wild-type	C323S
Specific activity (μmol min−1 mg−1)c	150 ± 6d	117 ± 5d	159	348	350
Km (S-HMG-CoA, μm)	28 ± 3	24 ± 2	24	45	8
Km (Mg2+, μm)	49 ± 7	88 ± 9	233	322	50
Km (Mn2+, μm)	0.18 ± 0.06	0.24 ± 0.06	0.34	0.37	10

^a Properties of human wild-type and C323S HMG-CoA lyase have been described by Roberts et al. (20).

^b Properties of avian HMG-CoA lyase have been described by Kramer and Miziorko (16) and Hruz and Miziorko (21).

^c Specific activities determined in the presence of 5 mm DTT.

^d Maximum specific activity is observed at 2.5 mm Mg²⁺.