GO:0008396 oxysterol 7-alpha-hydroxylase activity with no cross reference

[raymond91125]

GO:0008396 oxysterol 7-alpha-hydroxylase activity lacks EC/RHEA cross references. PMID:10882791 the reference cited for the definition does not seem to have anything to do with oxysterol. It must be a typo. A good reference PMID:9295351 Identification and Characterization of a Mouse Oxysterol 7a-Hydroxylase cDNA* PMID:10748047 Expression cloning of an oxysterol 7alpha-hydroxylase selective for 24-hydroxycholesterol PMID:27687912 Oxysterols: From cholesterol metabolites to key mediators. Mentions human/mouse CPY7B1 and CYP39A1.

[raymond91125]

oxysterols are oxidized cholesterols (sterols); Sterols are a subgroup of steroids that contain a hydroxyl group (-OH) at the third carbon position; Steroids are a broad class of lipids characterized by a core structure of four fused carbon rings (three cyclohexane rings and one cyclopentane ring).

Thus, GO:0008396 oxysterol 7-alpha-hydroxylase activity should be a subclass of GO:0008387 steroid 7-alpha-hydroxylase activity. (GO:0008396 EXP annotations include 2 genes, CYP39A1 and CYP7B1.) GO:0008123 cholesterol 7-alpha-monooxygenase activity should also be a subclass of GO:0008387 steroid 7-alpha-hydroxylase activity. (GO:0008123 EXP has only one gene (rat/mouse/human) CYP7A1.)

GO:0008387 steroid 7-alpha-hydroxylase activity has one EXP annotation of CYP39A1 and the definition has no publication reference, but has a narrow synonym cytochrome P450 CYP2A12. UniProt assigns CYP2A12 with EC:1.14.14.1 unspecific monooxygenase

Per UniProt, Expasy, and RHEA: CYP7B1 is of EC:1.14.14.29 25/26-hydroxycholesterol 7alpha-hydroxylase, RHEA:24308 and RHEA:19041, GO:0033783 CYP39A1 is of EC:1.14.14.26 24-hydroxycholesterol 7alpha-hydroxylase, RHEA:46124, GO:0033782 CYP7B1 is also of EC:1.14.14.26

[raymond91125]

Related by not strictly relevant information: Most cytochrome P450 belong to E.C. 1.14.-.- but there are exceptions https://iubmb.org/wp-content/uploads/sites/10116/2018/12/Classification-of-cytochrome-P-450-enzymes-by-the-Enzyme-Commission.pdf. Useful resource for human P450 https://www.guidetopharmacology.org/GRAC/FamilyDisplayForward?familyId=242

CYP2A12 (the narrow synonym for GO:0008387 steroid 7-alpha-hydroxylase activity) is a bile acid 7-alpha hydroxylase. Per PMID:31645370 CYP2A12 converts deoxycholic acid (DCA) -> cholic acid and lithocholic acid (LCA) -> cheno-deoxycholic acid (CDCA).

[pgaudet]

PMID:10882791 the reference cited for the definition does not seem to have anything to do with oxysterol. It must be a typo.

This reference was still present; removed.

[pgaudet]

Obsolete steroid 22-alpha hydroxylase activity and replace by steroid 22S-hydroxylase activity; represent the same activity.

[pgaudet]

oxysterol 7-alpha-hydroxylase activity seems to correspond to RHEA:68740 7-oxocholesterol + H+ + NADPH = 7alpha-hydroxycholesterol + NADP+

• [x] Added xref
• [x] Removed children 24S-hydroxycholesterol 7alpha-hydroxylase activity and 25-hydroxycholesterol 7alpha-hydroxylase activity since these are not children in RHEA.

[pgaudet]

• [x] steroid 17-alpha-monooxygenase activity
• [x] steroid 21-monooxygenase activity
• [x] testosterone 16-alpha-hydroxylase activity
• [x] GO:0031073 cholesterol 26-hydroxylase activity change parent from is_a: GO:0016705 ! oxidoreductase activity, acting on paired donors, with incorporation or reduction of molecular oxygen to +is_a: GO:0016712 ! oxidoreductase activity, acting on paired donors, with incorporation or reduction of molecular oxygen, reduced flavin or flavoprotein as one donor, and incorporation of one atom of oxygen

[pgaudet]

GO:0008123 cholesterol 7-alpha-monooxygenase activity Change definition to match RHEA:

• old def: "Catalysis of the reaction: cholesterol + NADPH + H+ + O2 = 7-alpha-hydroxycholesterol + NADP+ + H2O." [EC:1.14.14.23] +new def: "Catalysis of the reaction: cholesterol + O2 + reduced [NADPH—hemoprotein reductase] = 7alpha-hydroxycholesterol + H+ + H2O + oxidized [NADPH—hemoprotein reductase]." [EC:1.14.14.23]

And change parent from oxidoreductase activity, acting on paired donors, with incorporation or reduction of molecular oxygen, NAD(P)H as one donor, and incorporation of one atom of oxygen to GO:0016712 ! oxidoreductase activity, acting on paired donors, with incorporation or reduction of molecular oxygen, reduced flavin or flavoprotein as one donor, and incorporation of one atom of oxygen