diff --git a/model/src/main/java/lcsb/mapviewer/model/map/species/field/ModificationResidue.java b/model/src/main/java/lcsb/mapviewer/model/map/species/field/ModificationResidue.java
index 6696a13000f88ddae64514fb45ea4847cd82332e..46c4f6b22cc29d447619bb336c6be769e98d593c 100644
--- a/model/src/main/java/lcsb/mapviewer/model/map/species/field/ModificationResidue.java
+++ b/model/src/main/java/lcsb/mapviewer/model/map/species/field/ModificationResidue.java
@@ -35,7 +35,7 @@ import lcsb.mapviewer.model.map.species.Species;
 @DiscriminatorColumn(name = "modification_type", discriminatorType = DiscriminatorType.STRING)
 @DiscriminatorValue("GENERIC_MODIFICATION_RESIDUE")
 @org.hibernate.annotations.GenericGenerator(name = "test-increment-strategy", strategy = "increment")
-public class ModificationResidue implements Serializable {
+public abstract class ModificationResidue implements Serializable {
 
   /**
    *