The amino acid (aa) sequence of the leuB gene product of Salmonella typhimurium, 3-isopropylmalate dehydrogenase (IPMDH), has been revised using electron density maps from X-ray structure determination. The nucleotide (nt) sequence of both strands of leuB has been redetermined to confirm the crystallographic findings. It does not agree with the previously reported S. typhimurium leuB nucleotide sequence [Andreadis and Rosenthal, Biochim. Biophys. Acta 1129 (1992) 228-230].