Cytochrome P450, family 17, subfamily A, polypeptide 1
Symbols CYP17A1; CPT7; CYP17; P450C17; S17AH
External IDs OMIM609300 MGI88586 HomoloGene73875 GeneCards: CYP17A1 Gene
EC number
RNA expression pattern
PBB GE CYP17A1 205502 at tn.png
More reference expression data
Species Human Mouse
Entrez 1586 13074
Ensembl ENSG00000148795 ENSMUSG00000003555
UniProt P05093 Q3UYU1
RefSeq (mRNA) NM_000102.3 NM_007809.3
RefSeq (protein) NP_000093.1 NP_031835.3
Location (UCSC) Chr 10:
104.59 – 104.6 Mb
Chr 19:
46.74 – 46.75 Mb
PubMed search [1] [2]

CYP17A1 also known as cytochrome P450 17A1, or steroid 17-alpha-monooxygenase, or 17α-hydroxylase/17,20 lyase/17,20 desmolase[1] is a cytochrome P450 enzyme that 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 that 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 17 alpha-hydroxylase deficiency, 17 alpha-hydroxylase/17,20-lyase deficiency, pseudohermaphroditism, and adrenal hyperplasia.[2]



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

Additional images

See also


Further reading

  • Miura K, Yasuda K, Yanase T et al. (1996). "Mutation of cytochrome P-45017 alpha gene (CYP17) in a Japanese patient previously reported as having glucocorticoid-responsive hyperaldosteronism: with a review of Japanese patients with mutations of CYP17". J. Clin. Endocrinol. Metab. 81 (10): 3797–801. doi:10.1210/jc.81.10.3797. PMID 8855840. 
  • Miller WL, Geller DH, Auchus RJ (1999). "The molecular basis of isolated 17,20 lyase deficiency". Endocr. Res. 24 (3–4): 817–25. doi:10.3109/07435809809032692. PMID 9888582. 
  • Strauss JF (2004). "Some new thoughts on the pathophysiology and genetics of polycystic ovary syndrome". Ann. N. Y. Acad. Sci. 997: 42–8. doi:10.1196/annals.1290.005. PMID 14644808. 
  • Haider S, Patel J, Poojari C, Neidle S (2010). "Molecular modeling on inhibitor complexes and active-site dynamics of cytochrome P450 C17, a target for prostate cancer therapy". J. Mol Biol 400 (5): 1078–098. doi:10.1016/j.jmb.2010.05.069. PMID 20595043. 

External links