Sequence alignment of the regions around the conserved catalytic Cys-302 and Arg residues in MSDHs and comparison with other ALDHs. The sequence alignment includes some MSDHs whose activity has been demonstrated. Sequence alignment was performed with the BioEdit software, and the numbering of amino acid residues is according to Wang and Weiner (8). The conserved catalytic Cys-302 and the Arg-124 and Arg-301 residues, which are only conserved in MSDH and GAPN sequences, are highlighted. Sequences of 19 GAPNs and 40 hydrolytic and CoA-dependent ALDHs (excluding GAPNs) from the EMBL, Swiss-Prot, GenBankTM, and Pir databases were aligned to determine the consensus sequences.