Steroid 11-beta-hydroxylase

Steroid 11-beta-hydroxylase

Cytochrome P450, family 11, subfamily B, polypeptide 1
Identifiers
Symbols  ; CPN1; CYP11B; FHI; P450C11
External IDs ChEMBL: GeneCards:
EC number
RNA expression pattern
Orthologs
Species Human Mouse
Entrez
Ensembl
UniProt
RefSeq (mRNA)
RefSeq (protein)
Location (UCSC)
PubMed search

Steroid 11β-hydroxylase is a steroid hydroxylase found in the zona glomerulosa and zona fasciculata. Named officially the cytochrome P450 11B1, mitochondrial, it is a protein that in humans is encoded by the CYP11B1 gene.[1][2]

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 mitochondrial inner membrane and is involved in the conversion of 11-deoxycortisol to cortisol in the adrenal cortex. Transcript variants encoding different isoforms have been noted for this gene.[2]

It is reversibly inhibited by etomidate [3][4] and metyrapone.

Contents

  • Function 1
  • Mechanism of action 2
  • Regulation 3
  • Clinical significance 4
  • Additional images 5
  • References 6
  • Further reading 7
  • External links 8

Function

steroid 11β-monooxygenase
Identifiers
EC number 1.14.15.4
CAS number 9029-66-7
Databases
IntEnz IntEnz view
BRENDA BRENDA entry
ExPASy NiceZyme view
KEGG KEGG entry
MetaCyc metabolic pathway
PRIAM profile
PDB structures RCSB PDB PDBe PDBsum
Gene Ontology AmiGO / EGO

It generates cortisol from 11-deoxycortisol and corticosterone from 11-deoxycorticosterone. Note the extra "–OH" added at the 11 position (near the center, on ring "C"):

Mechanism of action

As a mitochondrial P450 system, P450c11 is dependent on two electron transfer proteins, adrenodoxin reductase and adrenodoxin that transfer 2 electrons from NADPH to the P450 for each monooxygenase reaction catalyzed by the enzyme. In most respects this process of electron transfer appears similar to that of P450scc system that catalyzes cholesterol side chain cleavage.[5] Similar to P450scc the process of electrons transfer is leaky leading to superoxide production. The rate of electron leakage during metabolism depends on the functional groups of the steroid substrate.[6]

Regulation

The expression of the enzyme in adrenocortical cells is regulated by the trophic hormone corticotropin (ACTH.[7]

Clinical significance

A mutation is associated with congenital adrenal hyperplasia due to 11β-hydroxylase deficiency.

Additional images

Steroidogenesis, showing steroid 11-beta-hydroxylase vertically at right.

References

  1. ^ Lifton RP, Dluhy RG, Powers M, Rich GM, Gutkin M, Fallo F, Gill JR Jr, Feld L, Ganguly A (Jun 1993). "Hereditary hypertension caused by chimaeric gene duplications and ectopic expression of aldosterone synthase". Nat Genet 2 (1): 66–74.  
  2. ^ a b "Entrez Gene: CYP11B1 cytochrome P450, family 11, subfamily B, polypeptide 1". 
  3. ^ Dörr HG, Kuhnle U, Holthausen H, Bidlingmaier F, Knorr D (November 1984). "Etomidate: a selective adrenocortical 11 beta-hydroxylase inhibitor". Klinische Wochenschrift 62 (21): 1011–3.  
  4. ^ Carol L. Lake (7 December 2004). Pediatric Cardiac Anesthesia. Lippincott Williams & Wilkins. p. 68.  
  5. ^ Hanukoglu I, Privalle CT, Jefcoate CR (May 1981). "Mechanisms of ionic activation of adrenal mitochondrial cytochromes P-450scc and P-45011 beta". J. Biol. Chem. 256 (9): 4329–35.  
  6. ^ Rapoport R, Sklan D, Hanukoglu I (March 1995). "Electron leakage from the adrenal cortex mitochondrial P450scc and P450c11 systems: NADPH and steroid dependence". Arch. Biochem. Biophys. 317 (2): 412–6.  
  7. ^ Hanukoglu I, Feuchtwanger R, Hanukoglu A (November 1990). "Mechanism of corticotropin and cAMP induction of mitochondrial cytochrome P450 system enzymes in adrenal cortex cells". J. Biol. Chem. 265 (33): 20602–8.  

Further reading

  • Helmberg A (August 1993). "Twin genes and endocrine disease: CYP21 and CYP11B genes". Acta Endocrinol. 129 (2): 97–108.  
  • Stowasser M, Gunasekera TG, Gordon RD (December 2001). "Familial varieties of primary aldosteronism". Clin. Exp. Pharmacol. Physiol. 28 (12): 1087–90.  
  • Helmberg A, Ausserer B, Kofler R (November 1992). "Frame shift by insertion of 2 basepairs in codon 394 of CYP11B1 causes congenital adrenal hyperplasia due to steroid 11 beta-hydroxylase deficiency". J. Clin. Endocrinol. Metab. 75 (5): 1278–81.  
  • Pascoe L, Curnow KM, Slutsker L, Connell JM, Speiser PW, New MI, White PC (September 1992). "Glucocorticoid-suppressible hyperaldosteronism results from hybrid genes created by unequal crossovers between CYP11B1 and CYP11B2". Proc. Natl. Acad. Sci. U.S.A. 89 (17): 8327–31.  
  • Kawamoto T, Mitsuuchi Y, Toda K, Yokoyama Y, Miyahara K, Miura S, Ohnishi T, Ichikawa Y, Nakao K, Imura H (February 1992). "Role of steroid 11 beta-hydroxylase and steroid 18-hydroxylase in the biosynthesis of glucocorticoids and mineralocorticoids in humans". Proc. Natl. Acad. Sci. U.S.A. 89 (4): 1458–62.  
  • White PC, Dupont J, New MI, Leiberman E, Hochberg Z, Rösler A (May 1991). "A mutation in CYP11B1 (Arg-448----His) associated with steroid 11 beta-hydroxylase deficiency in Jews of Moroccan origin". J. Clin. Invest. 87 (5): 1664–7.  
  • Kawamoto T, Mitsuuchi Y, Toda K, Miyahara K, Yokoyama Y, Nakao K, Hosoda K, Yamamoto Y, Imura H, Shizuta Y (September 1990). "Cloning of cDNA and genomic DNA for human cytochrome P-45011 beta". FEBS Lett. 269 (2): 345–9.  
  • Mornet E, Dupont J, Vitek A, White PC (December 1989). "Characterization of two genes encoding human steroid 11 beta-hydroxylase (P-450(11) beta)". J. Biol. Chem. 264 (35): 20961–7.  
  • Chua SC, Szabo P, Vitek A, Grzeschik KH, John M, White PC (October 1987). "Cloning of cDNA encoding steroid 11 beta-hydroxylase (P450c11)". Proc. Natl. Acad. Sci. U.S.A. 84 (20): 7193–7.  
  • Naiki Y, Kawamoto T, Mitsuuchi Y, Miyahara K, Toda K, Orii T, Imura H, Shizuta Y (December 1993). "A nonsense mutation (TGG [Trp116]-->TAG [Stop]) in CYP11B1 causes steroid 11 beta-hydroxylase deficiency". J. Clin. Endocrinol. Metab. 77 (6): 1677–82.  
  • Joehrer K, Geley S, Strasser-Wozak EM, Azziz R, Wollmann HA, Schmitt K, Kofler R, White PC (October 1997). "CYP11B1 mutations causing non-classic adrenal hyperplasia due to 11 beta-hydroxylase deficiency". Hum. Mol. Genet. 6 (11): 1829–34.  
  • Cargill M, Altshuler D, Ireland J, Sklar P, Ardlie K, Patil N, Shaw N, Lane CR, Lim EP, Kalyanaraman N, Nemesh J, Ziaugra L, Friedland L, Rolfe A, Warrington J, Lipshutz R, Daley GQ, Lander ES (July 1999). "Characterization of single-nucleotide polymorphisms in coding regions of human genes". Nat. Genet. 22 (3): 231–8.  
  • Halushka MK, Fan JB, Bentley K, Hsie L, Shen N, Weder A, Cooper R, Lipshutz R, Chakravarti A (July 1999). "Patterns of single-nucleotide polymorphisms in candidate genes for blood-pressure homeostasis". Nat. Genet. 22 (3): 239–47.  
  • Cao PR, Bernhardt R (June 1999). "Interaction of CYP11B1 (cytochrome P-45011 beta) with CYP11A1 (cytochrome P-450scc) in COS-1 cells". Eur. J. Biochem. 262 (3): 720–6.  
  • Loidi L, Quinteiro C, Barros F, Domínguez F, Barreiro J, Pombo M (December 1999). "The C494F variant in the CYP11B1 gene is a sequence polymorphism in the Spanish population". J. Clin. Endocrinol. Metab. 84 (12): 4749.  
  • Chabre O, Portrat-Doyen S, Chaffanjon P, Vivier J, Liakos P, Labat-Moleur F, Chambaz E, Morel Y, Defaye G (November 2000). "Bilateral laparoscopic adrenalectomy for congenital adrenal hyperplasia with severe hypertension, resulting from two novel mutations in splice donor sites of CYP11B1". J. Clin. Endocrinol. Metab. 85 (11): 4060–8.  
  • Fisher A, Friel EC, Bernhardt R, Gomez-Sanchez C, Connell JM, Fraser R, Davies E (September 2001). "Effects of 18-hydroxylated steroids on corticosteroid production by human aldosterone synthase and 11beta-hydroxylase". J. Clin. Endocrinol. Metab. 86 (9): 4326–9.  
  • Hampf M, Dao NT, Hoan NT, Bernhardt R (September 2001). "Unequal crossing-over between aldosterone synthase and 11beta-hydroxylase genes causes congenital adrenal hyperplasia". J. Clin. Endocrinol. Metab. 86 (9): 4445–52.  

External links