GO:0042768 ecdysteroid 2-hydroxylase activity with no cross reference

[raymond91125]

GO:0042768 ecdysteroid 2-hydroxylase activity lacks a EC/RHEA cross reference.

The definition reference PMID:12177427 shows

[raymond91125]

Additional references
PMID:3199825, https://doi.org/10.1016/0020-1790(87)90088-6
It is the activity of a cytochrome P450 but there is not a RHEA reaction that matches.

[sjm41]

Hi @raymond91125

I searched for 2-deoxyecdysone in MetaCyc, and found MetaCyc:RXN-14679:
https://metacyc.org/reaction?orgid=META&id=RXN-14679#SUMMARY
2-deoxyecdysone + 2 reduced adrenodoxin + dioxygen + 2 H+ → ecdysone + 2 oxidized adrenodoxin + H2O

And on the references tab, I see PMID:12177427 listed.

So I think you can use MetaCyc:RXN-14679 as the term and def xref here.

[pgaudet]

RHEA created the following reactions

(1) RHEA:82351 (PMID:12177427)
2-deoxyecdysone + 2 reduced [adrenodoxin] + O2 + 2 H+ = ecdysone + 2 oxidized
[adrenodoxin] + H2O
for GO:0042768 ecdysteroid 2-hydroxylase activity: 2-deoxyecdysone + 2 reduced adrenodoxin + O2 + 2 H+ = ecdysone + 2 oxidized adrenodoxin + H2O. (MetaCyc:RXN-14679) = Q9VGH1

(2) RHEA:83255 (PMID:12177427)
2,22-dideoxyecdysone + 2 reduced [adrenodoxin] + O2 + 2 H+ = 22-deoxyecdysone

• 2 oxidized [adrenodoxin] + H2O

(3) RHEA:82347 (PMID:15350618)
2,22,25-trideoxyecdysone + 2 reduced [adrenodoxin] + O2 + 2 H+ =
2,22-dideoxyecdysone + 2 oxidized [adrenodoxin] + H2O
= GO:0035302 ecdysteroid 25-hydroxylase activity: Catalysis of the hydroxylation of an ecdysteroid at carbon position 25. = MetaCyc:RXN-14677 ? = Q9VWR5

(4) RHEA:82055 (EC 1.14.15.44)
2,22-dideoxyecdysone + 2 reduced [adrenodoxin] + O2 + 2 H+ = 2-deoxyecdysone +
2 oxidized [adrenodoxin] + H2O
= GO:0042767 ecdysteroid 22-hydroxylase activity: Catalysis of the hydroxylation of an ecdysteroid at carbon position 22. = MetaCyc:RXN-14681? = Q9NGX9

@sjm41
Do you want to add these mappings (to make sure they are right) ?

See also MetaCyc pathway META&id=PWY-7300

[pgaudet]

Another mail from @kaxelsen

Hi Pascale,

I just would like to add that your term ecdysteroid includes
3-dehydro-deoxyecdysone compoundands.
GO:0042767 is now covered by EC 1.14.15.44, for which the officicial reaction
is
RHEA:83295 3-dehydro-2,22-dideoxyecdysone + 2 reduced [adrenodoxin] + O2 + 2
H+ = 3-dehydro-2-deoxyecdysone + 2 oxidized [adrenodoxin] + H2O
The EC entry (https://www.enzyme-database.org/query.php?ec=1.14.15.44) also
mentions RHEA:83255 and
83299 3-dehydro-2,22,25-deoxyecdysone + 2 reduced [adrenodoxin] + O2 + 2 H+ =
3-dehydro-2,25-deoxyecdysone + 2 oxidized [adrenodoxin] + H2O (based on
information in pmid:20837145).

Cheers,
Kristian

[sjm41]

@pgaudet These new RHEA entries don't seem to be public yet, which means I should not (cannot) add them to GO yet, right?

[pgaudet]

yes you can add them.

[sjm41]

Oh, OK!

[sjm41]

I've reviewed the above, and I think this is what needs to be done:

---

id: GO:0042768
name: ecdysteroid 2-hydroxylase activity
def: "Catalysis of the reaction: 2-deoxyecdysone + 2 reduced adrenodoxin + O2 + 2 H+ = ecdysone + 2 oxidized adrenodoxin + H2O." [MetaCyc:RXN-14679, PMID:12177427]
comment: Note that in the ecdysteroidogenic pathway, this activity catalyzes the conversion of 2-deoxyecdysone to ecdysone. It can also catalyze the conversion of 2,22-dideoxyecdysone (ketotriol) to 22-deoxyecdysone.
xref: MetaCyc:RXN-14679
is_a: GO:0008395 ! steroid hydroxylase activity
is_a: GO:0016713 ! oxidoreductase activity, acting on paired donors, with incorporation or reduction of molecular oxygen, reduced iron-sulfur protein as one donor, and incorporation of one atom of oxygen

• Change and generalise def to: "Catalysis of the hydroxylation of an ecdysteroid at carbon position 2." (to cover all the substrate-specific activities and match the pattern of the other two terms below). Remove MetaCyc:RXN-14679 as def xref.

• Make/add the following as narrowMatch xrefs:
  RHEA:82351 = MetaCyc:RXN-14679 (EC:1.14.15.M22)
  2-deoxyecdysone + 2 reduced [adrenodoxin] + O2 + 2 H+ = ecdysone + 2 oxidized
  [adrenodoxin] + H2O

RHEA:83255
2,22-dideoxyecdysone + 2 reduced [adrenodoxin] + O2 + 2 H+ = 22-deoxyecdysone + 2 oxidized [adrenodoxin] + H2O

MetaCyc:RXN-24932 (EC:1.14.15.M22)
3-dehydro-2,25-dideoxyecdysone + 2 reduced adrenodoxin + dioxygen + 2 H+ → 3-dehydro-25-deoxyecdysone + 2 oxidized adrenodoxin + H2O

MetaCyc:RXN-14682 (EC:1.14.15.M22)
3-dehydro-2-deoxyecdysone + 2 reduced adrenodoxin + dioxygen + 2 H+ → 3-dehydroecdysone + 2 oxidized adrenodoxin + H2O

---

id: GO:0035302
name: ecdysteroid 25-hydroxylase activity
def: "Catalysis of the hydroxylation of an ecdysteroid at carbon position 25. Ecdysteroids are a group of polyhydroxylated ketosteroids which initiate post-embryonic development, particularly metamorphosis, in insects and other arthropods." [ISBN:0198506732, PMID:15350618]
comment: Note that in the ecdysteroidogenic pathway, this activity catalyzes the conversion of 2,22,25-trideoxyecdysone (3-beta,5-beta-ketodiol) to 2,22-dideoxyecdysone (3-beta,5-beta-ketotriol).
is_a: GO:0008395 ! steroid hydroxylase activity

• Add the following as narrowMatch xrefs:
  RHEA:82347 = MetaCyc:RXN-14677 (EC:1.14.14.M65)
  2,22,25-trideoxyecdysone + 2 reduced [adrenodoxin] + O2 + 2 H+ = 2,22-dideoxyecdysone + 2 oxidized [adrenodoxin] + H2O

MetaCyc:RXN-14680 (1.14.14.M65)
3-dehydro-2,22,25-deoxyecdysone + reduced [NADPH-hemoprotein reductase] + dioxygen → 3-dehydro-2,22-dideoxyecdysone + oxidized [NADPH-hemoprotein reductase] + H2O

• add is_a: GO:0016712
  name: 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 (=EC:1.14.14.-)

---

id: GO:0042767
name: ecdysteroid 22-hydroxylase activity
def: "Catalysis of the hydroxylation of an ecdysteroid at carbon position 22." [PMID:12177427]
comment: Note that in the ecdysteroidogenic pathway, this activity catalyzes the conversion of 2,22-dideoxyecdysone (ketotriol) to 2-deoxyecdysone.
is_a: GO:0008395 ! steroid hydroxylase activity

• Add EC 1.14.15.44 as exactMatch xref and def xref.
  Reaction: 3-dehydro-2,22-dideoxyecdysone + O2 + 2 reduced adrenodoxin + 2 H+ = 3-dehydro-2-deoxyecdysone + H2O + 2 oxidized adrenodoxin
  Comments: | This cytochrome P-450 (heme-thiolate) monooxygenase catalyses the second of three sequential hydroxylation reactions that occur during the biosynthesis of 20-hydroxyecdysone, the major molting hormone of arthropods. The enzyme also acts on 3-dehydro-2,22,25-deoxyecdysone and 2,22-dideoxyecdysone.

• Add '3-dehydro-2,22-dideoxyecdysone 22-hydroxylase' as narrow synonym (from EC)

• Add the following as narrowMatch xrefs:
  RHEA:82055 = MetaCyc:RXN-14678
  2,22-dideoxyecdysone + 2 reduced [adrenodoxin] + O2 + 2 H+ = 2-deoxyecdysone +
  2 oxidized [adrenodoxin] + H2O

RHEA:83299 = MetaCyc:RXN-24931
3-dehydro-2,22,25-deoxyecdysone + 2 reduced adrenodoxin + dioxygen + 2 H+ → 3-dehydro-2,25-dideoxyecdysone + 2 oxidized adrenodoxin + H2O

RHEA:83295 = MetaCyc:RXN-14681
3-dehydro-2,22-dideoxyecdysone + 2 reduced adrenodoxin + dioxygen + 2 H+ → 3-dehydro-2-deoxyecdysone + 2 oxidized adrenodoxin + H2O

• add is_a: GO:0016713 ! oxidoreductase activity, acting on paired donors, with incorporation or reduction of molecular oxygen, reduced iron-sulfur protein as one donor, and incorporation of one atom of oxygen (=EC:1.14.15.-)

[sjm41]

So, I was able to add the new RHEAs, but not the new EC (EC:1.14.15.44) - that's available at ExplorEnz but not yet at ENZYME. So I'll have to leave this ticket open until that's available and I can add it to GO:0042767.

[kaxelsen]

EC 1.14.15.44 will become available in release 2025_05 scheduled for April 9