Term Name:	sphingolipid delta-4 desaturase activity
Synonyms:	delta-4 sphingolipid desaturase activity
Definition:	Catalysis of the reaction: a dihydroceramide + 2 ferrocytochrome b5 + O2 + 2 H+ -> a sphingosine ceramide (aka (4E)-sphing-4-enine ceramide) + 2 ferricytochrome b5 + 2 H2O.
Ontology:	GO: Molecular Function [GO:0042284]    QuickGO    AmiGO