25-hydroxyvitamin D-1 alpha hydroxylase, mitochondrial (CYP27B1)

Catalyzes the conversion of 25-hydroxyvitamin D3 (25(OH)D3) into 1-alpha,25-dihydroxyvitamin D3 (1alpha,25(OH)(2)D3), and of 24,25-dihydroxyvitamin D3 (24,25(OH)(2)D3) to 1- alpha,24,25-trihydroxyvitamin D3 (1alpha,24,25(OH)(3)D3). Is also active with 25-hydroxy-24-oxo-vitamin D3.

Plays an essential role in normal bone growth, calcium metabolism, and tissue differentiation. .