Polypeptides capable of catalyzing the reductive amination of a 2-ketoacid to its corresponding D-amino acid are provided. The polypeptides can be prepared by mutagenesis of, e.g., a diaminopimelate dehydrogenase. Also provided is a method of making a D-amino acid using a catalytically active polypeptide, wherein a 2-ketoacid is allowed to contact the polypeptide in the presence of a nicotinamide cofactor and ammonia or an ammonia source.