Enables steroid 11-beta-monooxygenase activity. Acts upstream of or within several processes, including aldosterone biosynthetic process; drinking behavior; and regulation of systemic arterial blood pressure by hormone. Located in mitochondrion. Is expressed in adrenal gland and gland. Human ortholog(s) of this gene implicated in several diseases, including congenital adrenal hyperplasia; corticosterone methyloxidase deficiency 1; diabetes mellitus (multiple); hypertension (multiple); and primary hyperaldosteronism (multiple). Orthologous to several human genes including CYP11B2 (cytochrome P450 family 11 subfamily B member 2). [provided by Alliance of Genome Resources, Apr 2022]