catalytic activity:A steroid + AH(2) + O(2) = a 17-alpha-hydroxysteroid + A + H(2)O.,cofactor:Heme group.,disease:Defects in CYP17A1 are the cause of adrenal hyperplasia type 5 (AH5) [MIM:202110]. AH5 is a form of congenital adrenal hyperplasia, a common recessive disease due to defective synthesis of cortisol. Congenital adrenal hyperplasia is characterized by androgen excess leading to ambiguous genitalia in affected females, rapid somatic growth during childhood in both sexes with premature closure of the epiphyses and short adult stature. Four clinical types: "salt wasting" (SW, the most severe type), "simple virilizing" (SV, less severely affected patients), with normal aldosterone biosynthesis, "non-classic form" or late onset (NC or LOAH), and "cryptic" (asymptomatic).,enzyme regulation:Regulated predominantly by intracellular cAMP levels.,function:Conversion of pregnenolone and p

非质量问题不退换