Q64410 · CP17A_CAVPO

  • Protein
    Steroid 17-alpha-hydroxylase/17,20 lyase
  • Gene
    CYP17A1
  • Status
    UniProtKB reviewed (Swiss-Prot)
  • Amino acids
  • Protein existence
    Evidence at protein level
  • Annotation score
    5/5

Function

function

A cytochrome P450 monooxygenase involved in corticoid and androgen biosynthesis. Catalyzes 17-alpha hydroxylation of C21 steroids, which is common for both pathways. A second oxidative step, required only for androgen synthesis, involves an acyl-carbon cleavage. The 17-alpha hydroxy intermediates, as part of adrenal glucocorticoids biosynthesis pathway, are precursors of cortisol. Hydroxylates steroid hormones, pregnenolone and progesterone to form 17-alpha hydroxy metabolites, followed by the cleavage of the C17-C20 bond to form C19 steroids, dehydroepiandrosterone (DHEA) and androstenedione. Has 16-alpha hydroxylase activity. Catalyzes 16-alpha hydroxylation of 17-alpha hydroxy pregnenolone, followed by the cleavage of the C17-C20 bond to form 16-alpha-hydroxy DHEA. Also 16-alpha hydroxylates androgens, relevant for estriol synthesis. Mechanistically, uses molecular oxygen inserting one oxygen atom into a substrate, and reducing the second into a water molecule, with two electrons provided by NADPH via cytochrome P450 reductase (CPR; NADPH-ferrihemoprotein reductase).

Catalytic activity

  • a C21-steroid + O2 + reduced [NADPH--hemoprotein reductase] = a 17alpha-hydroxy-C21-steroid + H+ + H2O + oxidized [NADPH--hemoprotein reductase]
    This reaction proceeds in the forward direction.
    EC:1.14.14.19 (UniProtKB | ENZYME | Rhea)
  • O2 + progesterone + reduced [NADPH--hemoprotein reductase] = 17alpha-hydroxyprogesterone + H+ + H2O + oxidized [NADPH--hemoprotein reductase]
    This reaction proceeds in the forward direction.
    EC:1.14.14.19 (UniProtKB | ENZYME | Rhea)
  • O2 + pregnenolone + reduced [NADPH--hemoprotein reductase] = 17alpha-hydroxypregnenolone + H+ + H2O + oxidized [NADPH--hemoprotein reductase]
    This reaction proceeds in the forward direction.
    EC:1.14.14.19 (UniProtKB | ENZYME | Rhea)
  • 17alpha-hydroxyprogesterone + O2 + reduced [NADPH--hemoprotein reductase] = acetate + androst-4-ene-3,17-dione + 2 H+ + H2O + oxidized [NADPH--hemoprotein reductase]
    This reaction proceeds in the forward direction.
    EC:1.14.14.32 (UniProtKB | ENZYME | Rhea)
  • 17alpha-hydroxyprogesterone + O2 + reduced [NADPH--hemoprotein reductase] = 16alpha,17alpha-dihydroxyprogesterone + H+ + H2O + oxidized [NADPH--hemoprotein reductase]
    This reaction proceeds in the forward direction.
  • 16alpha,17alpha-dihydroxyprogesterone + O2 + reduced [NADPH--hemoprotein reductase] = 6beta,16alpha,17alpha-trihydroxyprogesterone + H+ + H2O + oxidized [NADPH--hemoprotein reductase]
    This reaction proceeds in the forward direction.
  • 17alpha-hydroxypregnenolone + O2 + reduced [NADPH--hemoprotein reductase] = 3beta-hydroxyandrost-5-en-17-one + acetate + 2 H+ + H2O + oxidized [NADPH--hemoprotein reductase]
    This reaction proceeds in the forward direction.
    EC:1.14.14.32 (UniProtKB | ENZYME | Rhea)
  • 16alpha,17alpha-dihydroxypregnenolone + O2 + reduced [NADPH--hemoprotein reductase] = 3beta,16alpha-dihydroxy-androst-5-en-17-one + acetate + 2 H+ + H2O + oxidized [NADPH--hemoprotein reductase]
    This reaction proceeds in the forward direction.
  • 3beta-hydroxyandrost-5-en-17-one + O2 + reduced [NADPH--hemoprotein reductase] = 3beta,16alpha-dihydroxy-androst-5-en-17-one + H+ + H2O + oxidized [NADPH--hemoprotein reductase]
    This reaction proceeds in the forward direction.
  • androst-4-ene-3,17-dione + O2 + reduced [NADPH--hemoprotein reductase] = 16alpha-hydroxyandrost-4-ene-3,17-dione + H+ + H2O + oxidized [NADPH--hemoprotein reductase]
    This reaction proceeds in the forward direction.

Cofactor

heme (UniProtKB | Rhea| CHEBI:30413 )

Activity regulation

Regulated predominantly by intracellular cAMP levels. The 17,20-lyase activity is stimulated by cytochrome b5, which acts as an allosteric effector increasing the Vmax of the lyase activity.

Pathway

Steroid hormone biosynthesis.
Steroid biosynthesis; glucocorticoid biosynthesis.

Features

Showing features for binding site.

TypeIDPosition(s)Description
Binding site442Fe (UniProtKB | ChEBI) of heme (UniProtKB | ChEBI); axial binding residue

GO annotations

AspectTerm
Cellular Componentendoplasmic reticulum membrane
Molecular Functionheme binding
Molecular Functioniron ion binding
Molecular Functionlyase activity
Molecular Functionsteroid 17-alpha-monooxygenase activity
Biological Processglucocorticoid biosynthetic process
Biological Processhormone biosynthetic process
Biological Processprogesterone metabolic process
Biological Processsteroid metabolic process

Keywords

Enzyme and pathway databases

Names & Taxonomy

Protein names

  • Recommended name
    Steroid 17-alpha-hydroxylase/17,20 lyase
  • EC number
  • Alternative names
    • 17-alpha-hydroxyprogesterone aldolase (EC:1.14.14.32
      ) . EC:1.14.14.32 (UniProtKB | ENZYME | Rhea)
    • CYPXVII
    • Cytochrome P450 17A1
    • Cytochrome P450-C17 (Cytochrome P450c17)
    • Steroid 17-alpha-monooxygenase

Gene names

    • Name
      CYP17A1
    • Synonyms
      CYP17

Organism names

  • Taxonomic identifier
  • Strain
    • English short hair
  • Taxonomic lineage
    Eukaryota > Metazoa > Chordata > Craniata > Vertebrata > Euteleostomi > Mammalia > Eutheria > Euarchontoglires > Glires > Rodentia > Hystricomorpha > Caviidae > Cavia

Accessions

  • Primary accession
    Q64410
  • Secondary accessions
    • Q64659

Proteomes

Subcellular Location

PTM/Processing

Features

Showing features for chain.

TypeIDPosition(s)Description
ChainPRO_00000519281-508Steroid 17-alpha-hydroxylase/17,20 lyase

Interaction

Protein-protein interaction databases

Structure

Family & Domains

Sequence similarities

Belongs to the cytochrome P450 family.

Phylogenomic databases

Family and domain databases

Sequence

  • Sequence status
    Complete
  • Length
    508
  • Mass (Da)
    57,026
  • Last updated
    1996-11-01 v1
  • Checksum
    5F7D6EBFB5B5CC8E
MWELVTLLGLILAYLFWPRQGSSGTKYPKSLPSLPVVGSLPFLPKSGHMHVNFFKLQKKYGPIYSFRLGSTTTVVIGHHQLARELLIKKGKEFSGRPLTTTVALLSDNGKGIAFADSSATWQLHRRLVLSSFSLFRDGEQKLENIICQELSALCDFLATCDGQVKDLSSSIFMTVVNIICMICFSVSYKEGDMELVTIRRFTTGFVNSLSDDNLVDIFPWLKIFPNKTLEMIRKYTEIRGAMLSKILKECKEKFRSDSVSNLIDLLIQAKVNENNNNSSLDQDSNLFSDKHILTTLGDIFGAGVETSSSVVLWVIAFLLHNPQVKKKIQEEIDHNVGFSRTPTFSDRNHLLMLEATIREVLRIRPVAPILIPHKANTDSSIGEFAIDKDTNVLVNLWALHHNEQEWDRPDQFMPERFLDPTGSQIIVPSSSYLPFGAGPRSCVGEALARQEIFLITAWLLQKFDLEVPEGGQLPSLEGIPKIVFLIDPFKVKITVRPAWKEAQAEGSA

Features

Showing features for sequence conflict.

TypeIDPosition(s)Description
Sequence conflict62in Ref. 2; AAB33048

Keywords

Sequence databases

Nucleotide SequenceProtein SequenceMolecule TypeStatus
X82878
EMBL· GenBank· DDBJ
CAA58059.1
EMBL· GenBank· DDBJ
Genomic DNA
S75277
EMBL· GenBank· DDBJ
AAB33048.1
EMBL· GenBank· DDBJ
mRNA

Genome annotation databases

Similar Proteins

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