TABLE 1

Kinetic parameters of mouse CYP27B1 for 25(OH)-19-nor-D3 and 25(OH)D3

Substrate
Product
kcat
Km
kcat/Km
min−1 μM
25(OH)-19-nor-D3 M1 — — 0.025 ± 0.010
25(OH)-19-nor-D3 M3 — — 0.080 ± 0.010
25(OH)D3
1α,25
19.8 ± 8.2
0.31 ± 0.20
71.4 ± 19.1

  • —, not determined as described under Results.