CYP17A1

From Wikipedia, the free encyclopedia

CYP17A1 (also known as 17α-hydroxylase/17,20 lyase/17,20 desmolase^[1]) is a cytochrome P450 enzyme which acts upon pregnenolone and progesterone to add a hydroxyl (-OH) group at carbon 17 of the steroid D ring (the hydroxylase activity), or acts upon 17-hydroxyprogesterone and 17-hydroxypregnenolone to split the side chain off the steroid nucleus (the lyase activity).

17α-hydroxylase converts pregnenolone and progesterone to their 17-hydroxy forms, and converts 17-hydroxypregnenolone and 17-hydroxyprogesterone to DHEA and androstenedione, respectively. It corresponds to the downward arrows in this reaction scheme.

This gene encodes a member of the cytochrome P450 superfamily of enzymes. The cytochrome P450 proteins are monooxygenases which catalyze many reactions involved in drug metabolism and synthesis of cholesterol, steroids and other lipids. This protein localizes to the endoplasmic reticulum. It has both 17alpha-hydroxylase and 17,20-lyase activities and is a key enzyme in the steroidogenic pathway that produces progestins, mineralocorticoids, glucocorticoids, androgens, and estrogens. Mutations in this gene are associated with isolated steroid-17 alpha-hydroxylase deficiency, 17-alpha-hydroxylase/17,20-lyase deficiency, pseudohermaphroditism, and adrenal hyperplasia.^[2]

[edit] Additional images

Steroidogenesis, showing, at left side, both reactions of 17-alpha hydroxylase, and both actions of 17, 20 lyase.

Pregnenolone	17-Hydroxypregnenolone	Progesterone	17-Hydroxyprogesterone
Steroid numbering

[edit] See also

• Congenital adrenal hyperplasia due to 17 alpha-hydroxylase deficiency

[edit] External links

• MeSH CYP17A1+protein,+human

[edit] References

[edit] Further reading

This enzyme-related article is a stub. You can help Wikipedia by expanding it.