Table 2

Estradiol hydroxylation activities of CYP1B1 wild type and variantsa

CYP1B12-OH-estradiol4-OH-estradiol4-OH-E2:2-OH-E216α-OH-estradiol
Kmm)kcat (min−1)kcat/Km (mm−1 min−1)Kmm)kcat (min−1)kcat/Km (mm−1 min−1)Kcat/KmKmm)kcat (min−1)kcat/Km (mm−1 min−1)
Wild type34 ± 41.9 ± 0.155 ± 740 ± 84.4 ± 0.4110 ± 242.0 ± 0.539 ± 60.30 ± 0.027.6 ± 1.3
Variant 129 ± 53.2 ± 0.2110 ± 2019 ± 26.0 ± 0.2320 ± 353.0 ± 0.665 ± 90.56 ± 0.048.6 ± 1.3
Variant 218 ± 22.3 ± 0.1130 ± 1510 ± 13.8 ± 0.1370 ± 383.0 ± 0.541 ± 60.34 ± 0.028.4 ± 1.3
Variant 321 ± 22.2 ± 0.1110 ± 1211 ± 13.7 ± 0.1330 ± 313.0 ± 0.419 ± 10.31 ± 0.0116 ± 1.0
Variant 439 ± 52.8 ± 0.271 ± 1017 ± 24.5 ± 0.3270 ± 363.8 ± 0.829 ± 30.39 ± 0.0214 ± 1.6
Variant 529 ± 32.5 ± 0.186 ± 1015 ± 24.4 ± 0.1290 ± 393.3 ± 0.643 ± 70.40 ± 0.039.4 ± 1.7
  • a Data represent means ± SEs of duplicate assays. Hydroxylation reactions were conducted as described in “Materials and Methods.”