The gene encoding the glutamate dehydrogenase in Lactococcus lactis is part of a remnant Tn3 transposon carried by a large plasmid.

The gene responsible for the uncommon glutamate dehydrogenase (GDH) activity of Lactococcus lactis was identified and characterized. It encodes a GDH of family I that is mainly active in glutamate biosynthesis, is carried by a large plasmid, and is included, with functional cadmium resistance genes, in a remnant Tn3-like transposon.