diff --git a/src/ontology/go-edit.obo b/src/ontology/go-edit.obo
index 1b66954706..32d0c29a59 100644
--- a/src/ontology/go-edit.obo
+++ b/src/ontology/go-edit.obo
@@ -141619,6 +141619,8 @@ namespace: biological_process
 def: "The reduction of nitrate to dinitrogen by four reactions; each intermediate is transformed to the next lower oxidation state; also part of cellular bioenergetics; the nitrogen compounds can serve as terminal acceptors for electron transport phosphorylation in place of oxygen." [MetaCyc:DENITRIFICATION-PWY]
 xref: MetaCyc:DENITRIFICATION-PWY
 is_a: GO:0071941 ! nitrogen cycle metabolic process
+relationship: starts_with GO:0008940 ! nitrate reductase activity
+relationship: ends_with GO:0050304 ! nitrous-oxide reductase activity
 
 [Term]
 id: GO:0019334