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Literature summary for 1.14.14.32 extracted from

  • Akhtar, M.K.; Kelly, S.L.; Kaderbhai, M.A.
    Cytochrome b5 modulation of 17alpha hydroxylase and 17-20 lyase (CYP17) activities in steroidogenesis (2005), J. Endocrinol., 187, 267-274.
    View publication on PubMed
Search for more literature for 1.14.14.32

Organism

Organism UniProt Comment Textmining
Homo sapiens
-
-
-

Source Tissue

Source Tissue Comment Organism Textmining
adrenal cortex zona fasciculata, zona reticularis Homo sapiens
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gonad
-
 Homo sapiens
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Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
17alpha-Hydroxypregnenolone
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 Homo sapiens Dehydroepiandrosterone + acetaldehyde
-
 ?
17alpha-hydroxyprogesterone + [reduced NADPH-hemoprotein reductase] + O2
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 Homo sapiens androstenedione + acetate + [oxidized NADPH-hemoprotein reductase] + H2O
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 ?
additional information enzyme also catalyzes hydroxylation of pregnenolone to 17alpha-hydroxypregnenolone and of progesterone to 17alpha-hydroxyprogesterone Homo sapiens ?
-
 ?

Synonyms

Synonyms Comment Organism
17-20 lyase
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 Homo sapiens
CYP17
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 Homo sapiens

Cofactor

Cofactor Comment Organism Structure
cytochrome b5 enzyme shows dual functions - as a hydroxylase and as a lyase. The modulation of these two activities occurs through cytochrome b5. Association of cytochrome b5 and CYP17 is thought to be based primarily on electrostatic interactions in which the negatively charged residues pair up with positively charged residues on the proximal surface of the CYP17 molecule. Non-specific interactions of the hydrophobic membrane regions of cytochrome b5 and CYP17 are also thought to play a crucial role in the association of these two haemoproteins. Although cytochrome b5 is known to stimulate CYP activity by contributing the second electron in the catalytic cycle, in the case of CYP17, the mechanism of cleavage stimulation proceeds via an allosteric mode. It is hypothesised that cytochrome b5 promotes the cleavage by aligning the iron-oxygen complex attack onto the C20 rather than the C17 atom of the steroid substrate molecule Homo sapiens