Has a role in maintaining calcium homeostasis. Catalyzes the NADPH-dependent 24-hydroxylation of calcidiol (25-hydroxyvitamin D3) and calcitriol (1-alpha,25-dihydroxyvitamin D3). The enzyme can perform up to 6 rounds of hydroxylation of calcitriol leading to calcitroic acid. It also shows 23-hydroxylating activity leading to 1-alpha,25-dihydroxyvitamin D(3)-26,23-lactone as end product.
Chen K.-S., Proc. Natl. Acad. Sci. U.S.A. 90:4543-4547(1993).
Deloukas P., Nature 414:865-871(2001).
Chen K.-S., Biochim. Biophys. Acta 1263:1-9(1995).