<p>These are the glutathione synthetases found in Gram-negative bacteria. This gene does not appear to be present in genomes of Gram-positive bacteria. Glutathione synthetase has an ATP-binding domain in the COOH terminus and catalyzes the second step in the glutathione biosynthesis pathway: ATP + gamma-L-glutamyl-L-cysteine + glycine = ADP + phosphate + glutathione. Glutathione is a tripeptide that functions as a reductant in many cellular reactions. </p>