diff --git a/modules/io/src/mol/chemdict_parser.cc b/modules/io/src/mol/chemdict_parser.cc
index cf97f5e23d933c68a7fa6e5419027ae5b24cf534..9ff88e2f0a86ab236fc8074b59f392e8e92c931b 100644
--- a/modules/io/src/mol/chemdict_parser.cc
+++ b/modules/io/src/mol/chemdict_parser.cc
@@ -175,6 +175,9 @@ std::map<String, mol::ChemType> ChemdictParser::xtm_=std::map<String, mol::ChemT
 
 void ChemdictParser::InitTypeMap()
 {
+  // This list is manually kept up to date to include all types appearing in PDB
+  // See doc for how to create a compound library from scratch to test this
+  // https://openstructure.org/docs/conop/compoundlib/#creating-a-compound-library
   if (!tm_.empty())
     return;
   tm_["L-PEPTIDE COOH CARBOXY TERMINUS"]=mol::ChemClass(mol::ChemClass::L_PEPTIDE_LINKING);
@@ -184,6 +187,7 @@ void ChemdictParser::InitTypeMap()
   tm_["D-PEPTIDE NH3 AMINO TERMINUS"]=mol::ChemClass(mol::ChemClass::D_PEPTIDE_LINKING);
   tm_["D-BETA-PEPTIDE, C-GAMMA LINKING"]=mol::ChemClass(mol::ChemClass::D_PEPTIDE_LINKING);
   tm_["D-GAMMA-PEPTIDE, C-DELTA LINKING"]=mol::ChemClass(mol::ChemClass::D_PEPTIDE_LINKING);
+  tm_["L-SACCHARIDE, ALPHA LINKING"]=mol::ChemClass(mol::ChemClass::L_SACCHARIDE);
   tm_["L-SACCHARIDE 1,4 AND 1,4 LINKING"]=mol::ChemClass(mol::ChemClass::L_SACCHARIDE);
   tm_["D-SACCHARIDE 1,4 AND 1,4 LINKING"]=mol::ChemClass(mol::ChemClass::D_SACCHARIDE);
   tm_["L-SACCHARIDE"]=mol::ChemClass(mol::ChemClass::L_SACCHARIDE);