FB2026_03 , released September 17, 2026
CV Term Report
Help Close All Open All
General Information
Term cystathionine beta-synthase activity ID (Ontology) GO:0004122 (Gene Ontology)
Definition Catalysis of the reaction: L-serine + L-homocysteine = cystathionine + H2O.[ EC:4 ]
Comment
Links to External Ontologies
  QuickGO data     AmiGO data
Annotations
Records annotated with this term OR any of its CHILD TERMS

Choose a record type to view annotations for this term and its child terms. Direct annotations and full annotation statements below also provide HitList buttons.

    • Results list data from multiple species. Choose a record type above to open its HitList.
Direct annotations: records annotated with this exact term (child terms are NOT included)
Data ClassFieldDirect annotations
Genes (FBgn)GO_MOLECULAR_FUNCTION
show Full annotation statements including this term (annotations to child terms are NOT included), and relevant FlyBase records
 Full annotation statements 
Relevant FlyBase reports
 Genes
 cystathionine beta-synthase activity (all annotations which use CV term, excluding "NOT" statements)
     enables | cystathionine beta-synthase activity
Spanning Tree (Parents/Children)
Only view relationship:
Vocabulary search 
  carbon-oxygen lyase activity
   |__hydro-lyase activity
       |__cystathionine beta-synthase activity  1 rec.
Spanning Tree View Settings
Parents/Children
View Depth
Show hierarchy levels: for parents, for children
hide Relationships
Is a hydro-lyase activity
Part of
hide Synonyms & Secondary IDs
Synonyms
  • "beta-thionase activity" RELATED[ EC:4 ]
    "L-serine hydro-lyase (adding homocysteine)" RELATED[ EC:4 ]
    "L-serine hydro-lyase (adding homocysteine; L-cystathionine-forming)" RELATED[ EC:4 ]
    "methylcysteine synthase activity" RELATED[ EC:4 ]
    "serine sulfhydrase activity" RELATED[ EC:4 ]
    "serine sulfhydrylase activity" RELATED[ EC:4 ]
Secondary IDs
hide External Crossreferences & Linkouts
EC:4.2.1.22
MetaCyc:CYSTATHIONINE-BETA-SYNTHASE-RXN
Reactome:R-HSA-1614524 "PXLP-CBS tetramers condenses HCYS and L-Ser to form L-Cystathionine"
RHEA:10112