PMID-sentid Pub_year Sent_text comp_official_name comp_offsetprotein_name organism prot_offset 23769709-4 2013 Crucially, mitochondria are the starting point for steroid hormone biosynthesis, given that the conversion of cholesterol to pregnenolone (a common precursor for all steroid hormones) takes place via the activity of the cytochrome P450 side-chain cleavage enzyme (P450scc) on the inner mitochondrial membrane. Steroids 51-66 cytochrome P450 family 11 subfamily A member 1 Homo sapiens 264-271