Table 1

P450 enzyme activities exhibited by a panel of human lymphocyte microsomes containing cDNA-expressed human P450s

CYP	7-ECOD	Coumarin	7-EROD	7-BROD
1A1	⁺ ⁺ ⁺ ⁺ ⁺	−	⁺ ⁺ ⁺ ⁺ ⁺	⁺ ⁺ ⁺
1A2	⁺	−	⁺	(⁺)
1B1	−	−	(⁺)	⁺ ⁺
2A6	⁺	⁺ ⁺ ⁺ ⁺ ⁺	−	(⁺)
2B6	⁺	⁺ ⁺	−	⁺ ⁺
2C19	−	−	−	⁺ ⁺ ⁺
2C8	⁺	−	−	⁺ ⁺
2C9-Arg	−	−	−	⁺ ⁺ ⁺
2E1	⁺ ⁺	−	−	⁺
3A4	⁺	−	−	⁺ ⁺
4A11	−	−	−	⁺ ⁺

P450 enzyme activities were measured for a panel of 11 cDNA-expressed human P450s obtained from GENTEST Corp. using the assay methods described under Materials and Methods. Data obtained are summarized here in the form of a Table. “−” indicates the measured activity was below the limit of detection and “(⁺)” indicates activity was very low, but detectable. Higher activities are compared on a scale of “⁺” to “⁺⁺⁺⁺⁺”. Measured turnover numbers (pmol/min/pmol of P450) for CYP1A1 were approximately 4 (7-ECOD), 1 (7-EROD), and 5 (7-BROD). Coumarin hydroxylase data shown here are primarily based on Waxman et al. (1991).