diff --git a/paxtools-core/src/main/java/org/biopax/paxtools/impl/level3/CatalysisImpl.java b/paxtools-core/src/main/java/org/biopax/paxtools/impl/level3/CatalysisImpl.java
index <HASH>..<HASH> 100644
--- a/paxtools-core/src/main/java/org/biopax/paxtools/impl/level3/CatalysisImpl.java
+++ b/paxtools-core/src/main/java/org/biopax/paxtools/impl/level3/CatalysisImpl.java
@@ -90,7 +90,7 @@ public class CatalysisImpl extends ControlImpl implements Catalysis
 	@Override public void addController(Controller controller)
 	{
 		if (controller instanceof PhysicalEntity) super.addController(controller);
-		else throw new IllegalBioPAXArgumentException("Catalysis can only be controlled with a modulation");
+		else throw new IllegalBioPAXArgumentException("Catalysis can only be controlled with a Physical Entity");
 
 	}
Fixed a missed restriction check in Catalysis impl