diff --git a/netZooPy/condor/condor.py b/netZooPy/condor/condor.py
index bc5e95c5..92f7d9a9 100644
--- a/netZooPy/condor/condor.py
+++ b/netZooPy/condor/condor.py
@@ -304,9 +304,8 @@ def matrices(self, c,resolution):
 
             # Computes weighted biadjacency matrix.
             A = np.matrix(np.zeros((p, q)))
-            for edge in self.net.iterrows():
-                row = edge[1]
-                A[gn[row.iloc[1]], rg[row.iloc[0]]] = row.iloc[2]
+            for edge in self.net.itertuples(index=False):
+                A[gn[edge[1]], rg[edge[0]]] = edge[2]
 
             # Computes node degrees for the nodesets.
             ki = A.sum(1)
diff --git a/netZooPy/panda/__init__.py b/netZooPy/panda/__init__.py
index 4c994d56..d093c4d7 100755
--- a/netZooPy/panda/__init__.py
+++ b/netZooPy/panda/__init__.py
@@ -3,4 +3,4 @@
 from .panda import Panda
 from .analyze_panda import AnalyzePanda
 from .calculations import compute_panda
-from .io import load_motif, load_expression
+from .io import load_motif, load_expression, load_ppi
diff --git a/netZooPy/panda/io.py b/netZooPy/panda/io.py
index c399fa1c..da3bdcb9 100644
--- a/netZooPy/panda/io.py
+++ b/netZooPy/panda/io.py
@@ -74,4 +74,38 @@ def load_expression(expression_file, with_header = False, start = 1, end = None)
     return(expression_data, expression_genes, expression_samples)
 
 
-#def load_ppi(ppi_file):
+def load_ppi(ppi_file):
+    """Read PPI data from a file path or DataFrame.
+
+    Parameters
+    ----------
+        ppi_file : str or pd.DataFrame or None
+            Path to file containing the PPI data or a pandas DataFrame.
+            The PPI can be symmetrical; if not, it will be transformed into
+            a symmetrical adjacency matrix.
+            If None, returns (None, []).
+
+    Returns
+    -------
+        ppi_data : pd.DataFrame or None
+            PPI data as a DataFrame.
+        ppi_tfs : list
+            Sorted list of unique TFs in the PPI.
+    """
+    if type(ppi_file) is str:
+        ppi_data = pd.read_csv(ppi_file, sep="\t", header=None)
+        ppi_tfs = sorted(
+            set(pd.concat([ppi_data[0], ppi_data[1]]))
+        )
+    elif type(ppi_file) is not str:
+        if ppi_file is not None:
+            if not isinstance(ppi_file, pd.DataFrame):
+                raise Exception("Please provide a pandas dataframe for PPI data.")
+            ppi_data = ppi_file
+            ppi_tfs = sorted(
+                set(pd.concat([ppi_data[0], ppi_data[1]]))
+            )
+        else:
+            ppi_data = None
+            ppi_tfs = []
+    return (ppi_data, ppi_tfs)
diff --git a/netZooPy/panda/panda.py b/netZooPy/panda/panda.py
index bfc65c5c..6d947c7e 100755
--- a/netZooPy/panda/panda.py
+++ b/netZooPy/panda/panda.py
@@ -356,31 +356,17 @@ def processData(
             )
 
         ### Loading the PPI
-        # #TODO: move this to io
-        if isinstance(ppi_file, (str, os.PathLike)):
-            with Timer("Loading PPI data ..."):
-                self.ppi_data = pd.read_csv(ppi_file, sep="\t", header=None)
-                self.ppi_tfs = sorted(
-                    set(pd.concat([self.ppi_data[0], self.ppi_data[1]]))
-                )
-                print("Number of PPIs:", self.ppi_data.shape[0])
-        else:
-            if ppi_file is not None:
-                if not isinstance(ppi_file, pd.DataFrame):
-                    raise Exception("Please provide a pandas dataframe for PPI data.")
-                self.ppi_data = ppi_file  # pd.read_csv(ppi_file, sep='\t', header=None)
-                self.ppi_tfs = sorted(
-                    set(pd.concat([self.ppi_data[0], self.ppi_data[1]]))
-                )
-                print("Number of PPIs:", self.ppi_data.shape[0])
-            else:
-                # TODO: marouen, here we do not have an identiy matrix
-                print(
-                    "No PPI data given: ppi matrix will be an identity matrix of size",
-                    len(self.motif_tfs),
-                )
-                self.ppi_data = None
-                self.ppi_tfs = self.motif_tfs
+        with Timer("Loading PPI data ..."):
+            self.ppi_data, self.ppi_tfs = io.load_ppi(ppi_file)
+
+        if self.ppi_data is not None:
+            print("Number of PPIs:", self.ppi_data.shape[0])
+        elif ppi_file is None:
+            print(
+                "No PPI data given: ppi matrix will be an identity matrix of size",
+                len(self.motif_tfs),
+            )
+            self.ppi_tfs = self.motif_tfs
 
 
         ### Data combination