diff --git a/ippisite/ippidb/forms.py b/ippisite/ippidb/forms.py
index 29892e0bd5311ee7283a1326c87cdcc9e9df025a..8b8d64f5622ce12c4237a5c609721112ee6bb5be 100644
--- a/ippisite/ippidb/forms.py
+++ b/ippisite/ippidb/forms.py
@@ -1053,13 +1053,6 @@ class TestActivityDescriptionForm(forms.ModelForm):
         required=False,
     )
 
-    protein_complex = forms.ModelChoiceField(
-        queryset=models.Protein.objects.none(),
-        label=_("protein_domain_bound_complex_label"),
-        help_text=_("protein_domain_bound_complex_help_text"),
-        required=True,
-    )
-
     class Meta:
         model = models.TestActivityDescription
         fields = "__all__"
@@ -1115,13 +1108,6 @@ class TestActivityDescriptionForm(forms.ModelForm):
                     name=self.cleaned_data["cell_line_name"]
                 )
                 self.instance.cell_line = cell_line
-            if "protein_complex" in self.cleaned_data:
-                try:
-                    self.instance.protein_domain_bound_complex = self.complexes[
-                        self.cleaned_data["protein_complex"].pk
-                    ]
-                except KeyError:
-                    pass
         return super().save(commit=commit)
 
 
@@ -1148,13 +1134,6 @@ class TestActivityDescriptionBaseModelFormSet(BaseInlineNestedFormSet):
         )
         form.nested.set_compound_names(self.__compound_names)
         form.nested.set_modulation_type(self.__modulation_type)
-        form.fields["protein_complex"].queryset = models.Protein.objects.filter(
-            id__in=self.__protein_subset_ids
-        )
-        if models.Protein.objects.filter(id__in=self.__protein_subset_ids).count() == 1:
-            form.fields["protein_complex"].initial = models.Protein.objects.filter(
-                id__in=self.__protein_subset_ids
-            ).first()
 
     def set_compound_names(self, compound_names):
         """
@@ -1173,15 +1152,15 @@ class TestActivityDescriptionBaseModelFormSet(BaseInlineNestedFormSet):
         """
         self.__protein_subset_ids = protein_subset_ids
 
-    def set_complexes(self, complexes):
+    def set_complex(self, protein_domain_bound_complex):
         """
-        Provided to the form the complexes dictionary received from the wizard
+        Set the protein domain bound complex for all the form instances in the formset
 
         :param complexes:
         :return:
         """
         for form in self.forms:
-            form.complexes = complexes
+            form.instance.protein_domain_bound_complex = protein_domain_bound_complex
 
     def set_compounds(self, compounds):
         """
diff --git a/ippisite/ippidb/migrations/0052_auto_20200423_2019.py b/ippisite/ippidb/migrations/0052_auto_20200423_2019.py
new file mode 100644
index 0000000000000000000000000000000000000000..e25caeff611dac47a48882b0478e4f4f69e64e60
--- /dev/null
+++ b/ippisite/ippidb/migrations/0052_auto_20200423_2019.py
@@ -0,0 +1,19 @@
+# Generated by Django 2.2.1 on 2020-04-23 20:19
+
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('ippidb', '0051_remove_testactivitydescription_protein_bound_construct'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='testactivitydescription',
+            name='protein_domain_bound_complex',
+            field=models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.CASCADE, to='ippidb.ProteinDomainBoundComplex'),
+        ),
+    ]
diff --git a/ippisite/ippidb/models.py b/ippisite/ippidb/models.py
index 93733c7bee2aef1490759ad34dfca2c0f94832df..43e189f83bc0f39027568587f791026c4052a70e 100644
--- a/ippisite/ippidb/models.py
+++ b/ippisite/ippidb/models.py
@@ -1014,7 +1014,7 @@ class TestActivityDescription(models.Model):
     )
     biblio = models.ForeignKey(Bibliography, on_delete=models.CASCADE)
     protein_domain_bound_complex = models.ForeignKey(
-        ProteinDomainBoundComplex, on_delete=models.CASCADE
+        ProteinDomainBoundComplex, on_delete=models.CASCADE, null=True, blank=True
     )
     ppi = models.ForeignKey(Ppi, models.CASCADE, blank=True, null=True)
     test_type = models.CharField(
diff --git a/ippisite/ippidb/tests/test_activity_computation_and_storage_pIC50_2380_002_e-9.yaml b/ippisite/ippidb/tests/test_activity_computation_and_storage_pIC50_2380_002_e-9.yaml
index 61828344ddefb8c47d163b42fa6620df8b15aa0a..d23e8c9a7d11e94ced63753499e8129ef5fbcad1 100644
--- a/ippisite/ippidb/tests/test_activity_computation_and_storage_pIC50_2380_002_e-9.yaml
+++ b/ippisite/ippidb/tests/test_activity_computation_and_storage_pIC50_2380_002_e-9.yaml
@@ -8,7 +8,6 @@ activity_tests:
     modulation_type: I
   is_primary: true
   nb_active_compounds: 2
-  protein_complex: '2'
   test_modulation_type: I
   test_name: test
   test_type: BIOCH
diff --git a/ippisite/ippidb/tests/test_activity_computation_and_storage_pIC50_4_9846073_e-6.yaml b/ippisite/ippidb/tests/test_activity_computation_and_storage_pIC50_4_9846073_e-6.yaml
index 1206c5300107827a7bf7e42bb8b334f109bce52c..963453ff916c5671abe90aa1a69dc0f6e5c655ab 100644
--- a/ippisite/ippidb/tests/test_activity_computation_and_storage_pIC50_4_9846073_e-6.yaml
+++ b/ippisite/ippidb/tests/test_activity_computation_and_storage_pIC50_4_9846073_e-6.yaml
@@ -8,7 +8,6 @@ activity_tests:
     modulation_type: I
   is_primary: true
   nb_active_compounds: 2
-  protein_complex: '2'
   test_modulation_type: I
   test_name: test
   test_type: BIOCH
diff --git a/ippisite/ippidb/tests/test_activity_computation_and_storage_pIC50_639_39406_e-3.yaml b/ippisite/ippidb/tests/test_activity_computation_and_storage_pIC50_639_39406_e-3.yaml
index 306f48ab4f4e5edd11f77ce10281979ac1a6bbcd..8dd666a74fe8f9106e69b46166e717156c4bca40 100644
--- a/ippisite/ippidb/tests/test_activity_computation_and_storage_pIC50_639_39406_e-3.yaml
+++ b/ippisite/ippidb/tests/test_activity_computation_and_storage_pIC50_639_39406_e-3.yaml
@@ -8,7 +8,6 @@ activity_tests:
     modulation_type: I
   is_primary: true
   nb_active_compounds: 2
-  protein_complex: '2'
   test_modulation_type: I
   test_name: test
   test_type: BIOCH
diff --git a/ippisite/ippidb/tests/test_activity_computation_and_storage_pIC50_6_85_e-0.yaml b/ippisite/ippidb/tests/test_activity_computation_and_storage_pIC50_6_85_e-0.yaml
index eb93af6d979d60af273e12bf718ee02026fa7cbd..a11ee0b690e376ef4253a0d0571575582f3fed1f 100644
--- a/ippisite/ippidb/tests/test_activity_computation_and_storage_pIC50_6_85_e-0.yaml
+++ b/ippisite/ippidb/tests/test_activity_computation_and_storage_pIC50_6_85_e-0.yaml
@@ -8,7 +8,6 @@ activity_tests:
     modulation_type: I
   is_primary: true
   nb_active_compounds: 2
-  protein_complex: '2'
   test_modulation_type: I
   test_name: test
   test_type: BIOCH
diff --git a/ippisite/ippidb/tests/test_basic_entry.yaml b/ippisite/ippidb/tests/test_basic_entry.yaml
index 6f28b468b4f39c34c7678855243ecbef4f820d98..af3ac0d2a90e95ef8d83cf1c348a2d3f0946af0c 100644
--- a/ippisite/ippidb/tests/test_basic_entry.yaml
+++ b/ippisite/ippidb/tests/test_basic_entry.yaml
@@ -8,7 +8,6 @@ activity_tests:
     modulation_type: I
   is_primary: true
   nb_active_compounds: 2
-  protein_complex: '2'
   test_modulation_type: I
   test_name: test
   test_type: BIOCH
diff --git a/ippisite/ippidb/tests/test_complex_no_pfam.yaml b/ippisite/ippidb/tests/test_complex_no_pfam.yaml
index cc7429b468a22b53b2a7843a7c7d61be3015a34b..9ff962bf4fae400a8dc91f2f37d0ddff0233227c 100644
--- a/ippisite/ippidb/tests/test_complex_no_pfam.yaml
+++ b/ippisite/ippidb/tests/test_complex_no_pfam.yaml
@@ -8,7 +8,6 @@ activity_tests:
     modulation_type: I
   is_primary: true
   nb_active_compounds: 2
-  protein_complex: '1'
   test_modulation_type: I
   test_name: test
   test_type: BIOCH
diff --git a/ippisite/ippidb/tests/test_entry_28.yaml b/ippisite/ippidb/tests/test_entry_28.yaml
index 7fddcc4b3e6c9d4bc2d1028b0d197f6e3105407f..5923d9523d70ffdda832aea5ce80f94c55319a23 100644
--- a/ippisite/ippidb/tests/test_entry_28.yaml
+++ b/ippisite/ippidb/tests/test_entry_28.yaml
@@ -8,7 +8,6 @@ activity_tests:
     modulation_type: I
   is_primary: true
   nb_active_compounds: 1
-  protein_complex: '1'
   test_modulation_type: B
   test_name: biolayer interferometry assay
   test_type: BIOCH
diff --git a/ippisite/ippidb/tests/test_simple_heterodimer.yaml b/ippisite/ippidb/tests/test_simple_heterodimer.yaml
index 72cd7db1ececc61f71d004abaae8b4fcc9b317ff..31762772d1822d48aba3bb24f3cbd84864c7dd24 100644
--- a/ippisite/ippidb/tests/test_simple_heterodimer.yaml
+++ b/ippisite/ippidb/tests/test_simple_heterodimer.yaml
@@ -8,7 +8,6 @@ activity_tests:
     modulation_type: I
   is_primary: true
   nb_active_compounds: 2
-  protein_complex: '1'
   test_modulation_type: I
   test_name: test
   test_type: BIOCH
diff --git a/ippisite/ippidb/tests/test_simple_heterodimer_208.yaml b/ippisite/ippidb/tests/test_simple_heterodimer_208.yaml
index a3c8e2a874054d4d8a55df6d5cb90fba49f61f77..84608560d331b79483534668f836e6005f4c987f 100644
--- a/ippisite/ippidb/tests/test_simple_heterodimer_208.yaml
+++ b/ippisite/ippidb/tests/test_simple_heterodimer_208.yaml
@@ -33,7 +33,6 @@ activity_tests:
     test_modulation_type: I
     nb_active_compounds: 1
     cell_line_name: ''
-    protein_complex: '1'
     compound_activity_results:
     - activity_mol: 6
       activity_type: pIC50
@@ -46,7 +45,6 @@ activity_tests:
     test_modulation_type: I
     nb_active_compounds: 1
     cell_line_name: 'Human small-cell lung cancer'
-    protein_complex: '1'
     compound_activity_results:
     - activity_mol: 20
       activity_type: "KdRat"
diff --git a/ippisite/ippidb/tests/test_simple_stabilized_heterodimer.yaml b/ippisite/ippidb/tests/test_simple_stabilized_heterodimer.yaml
index 57c5b9236cb1275a6304ead85260cf8b4c609bbb..3dc5abcd9777d0071b571fc4513c95b311e41a4b 100644
--- a/ippisite/ippidb/tests/test_simple_stabilized_heterodimer.yaml
+++ b/ippisite/ippidb/tests/test_simple_stabilized_heterodimer.yaml
@@ -8,7 +8,6 @@ activity_tests:
     modulation_type: S
   is_primary: true
   nb_active_compounds: 2
-  protein_complex: '1'
   test_modulation_type: I
   test_name: pull down
   test_type: BIOCH
diff --git a/ippisite/ippidb/tests/test_stabilizer_204.yaml b/ippisite/ippidb/tests/test_stabilizer_204.yaml
index e7d9d13a1638fe9d2a596d55c857f2a5d3e77d5e..32e3ded658e247ef496275ba8f0e5a63f38f1854 100644
--- a/ippisite/ippidb/tests/test_stabilizer_204.yaml
+++ b/ippisite/ippidb/tests/test_stabilizer_204.yaml
@@ -30,7 +30,6 @@ activity_tests:
   test_name: Fluorescence Polarization
   test_modulation_type: B
   nb_active_compounds: 1
-  protein_complex: '1'
   compound_activity_results:
   - activity_mol: 20
     activity_type: pKd
diff --git a/ippisite/ippidb/tests/test_with_all_tests.yaml b/ippisite/ippidb/tests/test_with_all_tests.yaml
index 26fc81b4ca5037bec288f98b12aacb2ff5365d6c..154992d54674d638c69474d0d467e366f227c978 100644
--- a/ippisite/ippidb/tests/test_with_all_tests.yaml
+++ b/ippisite/ippidb/tests/test_with_all_tests.yaml
@@ -8,7 +8,6 @@ activity_tests:
     modulation_type: I
   is_primary: true
   nb_active_compounds: 2
-  protein_complex: '2'
   test_modulation_type: I
   test_name: test
   test_type: BIOCH
diff --git a/ippisite/ippidb/tests/tests_contribute_e2e.py b/ippisite/ippidb/tests/tests_contribute_e2e.py
index ad6959b049e379b8b540ce11bd4b54ca1b608d9c..09c8983fde9efe969cf90595573934c561a39c49 100644
--- a/ippisite/ippidb/tests/tests_contribute_e2e.py
+++ b/ippisite/ippidb/tests/tests_contribute_e2e.py
@@ -369,7 +369,6 @@ class ContributionE2ETestCase(TestCase):
                 ]
                 if "cell_line_name" in activity_test:
                     data[f"{idx}-cell_line_name"] = activity_test["cell_line_name"]
-                data[f"{idx}-protein_complex"] = activity_test["protein_complex"]
                 data[
                     f"{idx}-compoundactivityresult_set-activity-results-TOTAL_FORMS"
                 ] = 1  # len(activity_test.get("compound_activity_results",[]))
diff --git a/ippisite/ippidb/views/contribute.py b/ippisite/ippidb/views/contribute.py
index 6e88540f4d696272fe124bbefcc764506641c174..31e28ae6f31968aa2e1eb219b5d1323dc75c10e9 100644
--- a/ippisite/ippidb/views/contribute.py
+++ b/ippisite/ippidb/views/contribute.py
@@ -489,7 +489,13 @@ class IppiWizard(
 
             # Step 8.1 Activity Tests
             # We set the dicts to translates attributes into model
-            form_dict["ActivityDescriptionFormSet"].set_complexes(complexes)
+            bound_complexes = [
+                protein_domain_complex
+                for protein_domain_complex in complexes.values()
+                if isinstance(protein_domain_complex, models.ProteinDomainBoundComplex)
+            ]
+            if len(bound_complexes) == 1:
+                form_dict["ActivityDescriptionFormSet"].set_complex(bound_complexes[0])
             form_dict["ActivityDescriptionFormSet"].set_compounds(compounds)
             # We set the constants attributes among the instances to be created by the modelformset
             form_dict["ActivityDescriptionFormSet"].instance = dict(