. Author manuscript; available in PMC: 2012 Jul 1.

Published in final edited form as: Arch Biochem Biophys. 2011 Apr 13;511(1-2):48–55. doi: 10.1016/j.abb.2011.04.004

Table 2. Dependence of Activity of HMGCL Double Cys→Ser Mutants on Exogenous Thiol.

	Activity Recovered Following Reduction of Dialyzed Enzyme (U/mg)	Activity Following Dialysis (U/mg)	Stimulation of Activity by Exogenous Thiol	Intersubunit Dimer Formation^a

Enzyme	Reducing Assay Conditions	Non-Reducing Assay Conditions		Non-Reducing Assay Conditions
WT HMGCL	123 (± 7)	11.5 (± 1.4)	10.7 fold	Strong
C170S HL	53.1 (± 8.3)	0.084 (± 0.012)	636 fold	None
C170S/C174S HL	1.06 (± 0.01)	0.093 (± 0.022)	11.4 fold	Moderate
C170S/C266S HL	0.123 (± 0.021)	0.047 (± 0.008)	2.62 fold	None
C170S/C323S HL	18.5 (± 1.3)	0.662 (± 0.024)	27.9 fold	None

Strong indicates a SDS PAGE dimer band (Fig. 6B) which is >65% of the total intensity in that lane; moderate, 34-65%; weak, <34%.