What is the Origin of CYP17?

The term is derived from its membership in the Cytochrome P450 superfamily of enzymes, a large group of monooxygenases involved in the metabolism of various compounds. The '17' denotes its primary site of action, the 17th carbon position on the steroid molecule. The enzyme is a fundamental component of the classic steroidogenic cascade, a biochemical process conserved across many species for the production of vital steroid hormones.

What is the Mechanism of CYP17?

CYP17 possesses two distinct enzymatic activities: 17-alpha-hydroxylase and 17,20-lyase. The 17-alpha-hydroxylase activity converts pregnenolone and progesterone into their 17-hydroxy derivatives, a step required for glucocorticoid synthesis. Subsequently, the 17,20-lyase activity cleaves the side chain of these 17-hydroxy precursors, resulting in the formation of C19 steroids like dehydroepiandrosterone, which are the foundational androgens. This dual functionality is tightly regulated and dictates the flow of steroid production toward either cortisol or sex hormones.

CYP17

Meaning

CYP17, formally known as Cytochrome P450 17A1, is a critical microsomal enzyme that plays a central role in the steroidogenesis pathway. This enzyme is essential for the biosynthesis of glucocorticoids and all sex hormones, including androgens and estrogens. Its dual catalytic functions make it a pivotal checkpoint in the adrenal cortex and gonads, directing steroid precursors toward different hormonal end products. Genetic mutations or pharmacological inhibition of this enzyme can lead to significant hormonal imbalances.