Glutamate dehydrogenase of Halobacterium salinarum: evidence that the gene sequence currently assigned to the NADP +-dependent enzyme is in fact that of the NAD +-dependent glutamate dehydrogenase

Abstract

A GDH gene from Halobacterium salinarum has been cloned and sequenced and the publication assigns the sequence to the NADP +-glutamate dehydrogenase of this organism. We have expressed this gene in Escherichia coli and find that it encodes an NAD +-dependent glutamate dehydrogenase without activity towards NADP +. Further, peptide sequence from the two corresponding proteins supports the view that the deposited sequence is indeed that of the NAD +-dependent glutamate dehydrogenase. Sequence from the NAD +-dependent protein matches the published gene sequence, whereas sequence from the NADP + glutamate dehydrogenase does not.