Reactome | ALAD condenses 2 dALAs to form PBG

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ALAD condenses 2 dALAs to form PBG Show undefined attributes

catalystActivity	[CatalystActivity:10462974] porphobilinogen synthase activity of 8x(ALAD:Zn2+) [cytosol]
category	transition
compartment	[Compartment:70101] cytosol
created	[InstanceEdit:10447035] Weiser, Joel, 2026-03-16
dbId	10462978
displayName	ALAD condenses 2 dALAs to form PBG
eventOf	[Pathway:R-SSC-189451] Heme biosynthesis - Sus scrofa
evidenceType	[EvidenceType:9984902] inferred by electronic annotation
followingEvent	[Reaction:R-SSC-189406] 4 PBGs bind to form HMB - Sus scrofa
inferredFrom	[Reaction:R-HSA-189439] ALAD condenses 2 dALAs to form PBG - Homo sapiens
input	2 × [SimpleEntity:R-ALL-189489] dALA [cytosol]
isInDisease	false
isInferred	true
maxDepth	1
name	ALAD condenses 2 dALAs to form PBG 2 5-aminolevulinate => H(+) + 2 H2O + porphobilinogen Two molecules of ALA condense to form porphobilinogen (PBG)
output	[SimpleEntity:R-ALL-70106] H+ [cytosol] 2 × [SimpleEntity:R-ALL-29356] H2O [cytosol] [SimpleEntity:R-ALL-189464] PBG [cytosol]
regulatedBy	[NegativeRegulation:10462979] Negative regulation by '8xALAD:Pb2+:Zn2+ [cytosol]'
releaseDate	2026-03-25
schemaClass	Reaction
species	[Species:49633] Sus scrofa
stId	R-SSC-189439
summation	[Summation:9984901] This event has been computationally inferred from an event that has been demonstrated in another species. The inference is based on the homology mapping from PANTHER. Briefly, reactions for which all involved PhysicalEntities (in input, output and catalyst) have a mapped orthologue/paralogue (for complexes at least 75% of components must have a mapping) are inferred to the other species. High level events are also inferred for these events to allow for easier navigation. More details and caveats of the event inference in Reactome. For details on PANTHER see also: http://www.pantherdb.org/about.jsp

Referrals

(hasEvent)	[Pathway:R-SSC-189451] Heme biosynthesis
(precedingEvent)	[Reaction:R-SSC-189406] 4 PBGs bind to form HMB
(inferredTo)	[Reaction:R-HSA-189439] ALAD condenses 2 dALAs to form PBG

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