biopax-level3Pathway177726

<b>About this Pathway</b> This pathway describes the biosynthesis of aldosterone from the &delta; 5-3 hydroxy steroid, pregnenolone. The initial step is the catalysis of pregnenolone to progesterone. This conversion is carried out in two separate, sequential reactions, first the dehydrogenation of the 3&beta;-hydroxy steroid, producing pregn-5-ene-3,20-dione, followed by an isomerization to progesterone |CITS: [7673125]|. This is carried out by a multi-functional enzyme pregnenolone 3-dehydrogenase/progesterone isomerase encoded by HSD3&beta;1 and HSD3&beta;2 which differ in their expression patterns. The conversion of progesterone to 11-deoxycorticosterone is catalyzed by CYP21A2, a member of the cytochrome P450 superfamily of heme containing membrane associated enzymes |CITS: [3487786]|. These monooxygenases utilize NADPH for the reduction of molecular oxygen via a membrane bound microsomal electron transfer system. CYP21A2 localizes to the endoplasmic reticulum membrane and is expressed only in the adrenal cortex. CYP11B2, another member of the cytochrome P450 superfamily, localizes to the mitochondrial inner membrane and catalyzes the conversion of 11-deoxycortisone to aldosterone in three distinct reactions at a single active site |CITS: [1741400]|.

http://biocyc.org/biopax/biopax-level3Provenance125051, urn:biopax:Provenance:humancyc_16

aldosterone biosynthesis, corticosterone biosynthesis

http://biocyc.org/biopax/biopax-level3BiochemicalReaction134017, http://biocyc.org/biopax/biopax-level3BiochemicalReaction168633, http://biocyc.org/biopax/biopax-level3BiochemicalReaction169016, http://biocyc.org/biopax/biopax-level3BiochemicalReaction169067, http://biocyc.org/biopax/biopax-level3BiochemicalReaction169078, http://biocyc.org/biopax/biopax-level3BiochemicalReaction171861, http://biocyc.org/biopax/biopax-level3Catalysis134032, http://biocyc.org/biopax/biopax-level3Catalysis134034, http://biocyc.org/biopax/biopax-level3Catalysis168644, http://biocyc.org/biopax/biopax-level3Catalysis169033, http://biocyc.org/biopax/biopax-level3Catalysis169076, http://biocyc.org/biopax/biopax-level3Catalysis169080, http://biocyc.org/biopax/biopax-level3Catalysis171863, http://biocyc.org/biopax/biopax-level3Catalysis171865

mineralocorticoid biosynthesis