diff --git a/shapes/go-cam-shapes.shex b/shapes/go-cam-shapes.shex
index 4a49796..47201c5 100644
--- a/shapes/go-cam-shapes.shex
+++ b/shapes/go-cam-shapes.shex
@@ -405,7 +405,7 @@ PREFIX results_in_remodeling_of: <http://purl.obolibrary.org/obo/RO_0002591>
 
 <MolecularFunction> @<GoCamEntity> AND EXTRA a {
   a ( @<MolecularFunctionClass> OR @<NegatedMolecularFunctionClass> ) {1};
-  enabled_by:  ( @<InformationBiomacromolecule> OR @<ProteinContainingComplex> ) {0,1};
+  enabled_by:  ( @<InformationBiomacromolecule> OR @<ProteinContainingComplex> ) *;
   part_of: @<BiologicalProcess> *;
   has_part: @<MolecularFunction> *;
   occurs_in: @<AnatomicalEntity> {0,1};