diff --git a/spectrum_io/search_result/sage.py b/spectrum_io/search_result/sage.py
index 95eb4fb..0f1b76c 100644
--- a/spectrum_io/search_result/sage.py
+++ b/spectrum_io/search_result/sage.py
@@ -81,7 +81,7 @@ def update_columns_for_prosit(df: pd.DataFrame ) -> pd.DataFrame:
         df['SCORE'] = df['HYPERSCORE']
         # converting proforma to unimode
         print(df)
-        df['MODIFIED_SEQUENCE'] = sage_to_internal(df['MODIFIED_SEQUENCE'].to_numpy())
+        df['MODIFIED_SEQUENCE'] = sage_to_internal(df['MODIFIED_SEQUENCE'])
         
         print(df.columns)
         return df