Table 1.

Quantity and spectral properties of human P450 proteins expressed under different conditions

	Soret λmax	Total P450 from Soret peak	ASoreta/A280	P450b
	nm	nmol/liter culture		%
CYP3A4
CYP3A4/chaperone expressed in Terrific Broth in the presence of:
δ-Aminolevulinic acid/no ligand	416	240	1.54	82
CYP3A4/pHug/chaperone expressed in iron-depleted medium in the presence of:
FePPIX/no ligand	416	51	1.57	86
CYP21A2
CYP21A1/chaperone expressed in Terrific Broth in the presence of:
δ-Aminolevulinic acid/no ligand	419	350	1.2	54
CYP21A1/pHug/chaperone expressed in iron-depleted medium in the presence of:
No PPIX/no ligand	425	0.83	0.17	12
FePPIX/no ligand	418	37	1.07	81
FePPIX/progesterone (substrate)	419	83	1.18	89
CYP17A1
CYP17A1/chaperone expressed in Terrific Broth in the presence of:
δ-Aminolevulinic acid/no ligand	417	100	0.9	74
CYP17A1/pHug/chaperone expressed in iron-depleted medium in the presence of:
No PPIX/no ligand	Tracec	Trace	Trace	Trace
FePPIX/no ligand	416	6.8	1.25	39
FePPIX/progesterone (substrate)	416	23	1.28	75
FePPIX/abiraterone (inhibitor)	421	96	1.22	100
CoPPIX/abiraterone (inhibitor)	428	117	1.54	No peak
GaPPIX/abiraterone (inhibitor)d	421, 438	300	1.7	No peak
InPPIX/abiraterone (inhibitor)d	431	51	1.21	90
CuPPIX/abiraterone (inhibitor)d	422	40	1.04	100
ZnPPIX/abiraterone (inhibitor)d	426	108	1.4	100
AgPPIX/abiraterone (inhibitor)d	426	18	1.05	100

^a The absorbance of the Soret peak (heme) to absorbance at 280 nm (total protein) is a relative measure of purity for an individual P450 enzyme.

^b The percentage of P450 from the total of P450 and P420 species in the reduced, carbon monoxide difference spectrum reflects correct heme incorporation.

^c Trace, trace amounts of protein too little to characterize.

^d The CYP17A1 enzyme used was the A105L mutant, which has higher yields to help generate enough sample for NMR experiments.