What is the Origin of Steroidogenic Enzyme P450c17?

The enzyme's name is derived from its function as a cytochrome P450 monooxygenase, and the 'c17' denotes its action at the 17th carbon position of the steroid nucleus. Its discovery and characterization were essential steps in mapping the full steroidogenic cascade, revealing the key branching point that determines whether a steroid precursor is directed toward cortisol or toward androgen production. Genetic defects in this enzyme lead to profound disorders of sexual development and adrenal function.

What is the Mechanism of Steroidogenic Enzyme P450c17?

The enzyme is localized to the endoplasmic reticulum and utilizes NADPH as a co-factor to carry out its sequential reactions. The 17α-hydroxylase activity converts pregnenolone and progesterone into their 17α-hydroxylated forms, which are precursors to cortisol. Subsequently, the 17,20-lyase activity cleaves the side chain of the 17α-hydroxy precursors, generating the 19-carbon androgens DHEA and androst

Steroidogenic Enzyme P450c17 ∞ Area

Steroidogenic Enzyme P450c17

Meaning

A critical cytochrome P450 enzyme, formally known as CYP17A1, that occupies a pivotal position in the steroidogenesis pathway by catalyzing two distinct and essential reactions: 17α-hydroxylase activity and 17,20-lyase activity. This enzyme is primarily expressed in the adrenal glands and gonads, governing the synthesis of glucocorticoids, mineralocorticoids, and all sex steroid precursors, including dehydroepiandrosterone (DHEA) and androstenedione. Its precise regulation is fundamental to maintaining the balance of all adrenal and gonadal steroid hormones.