The GHRA subfamily comprises mostly bacterial enzymes (except for one protein from Nematostella vectensis, closely related to β-proteobacterial enzymes), out of which three (from E. coli, R. etli and S. meliloti) have been characterized biochemically. Unlike most GHRB members, which have hydroxypyruvate as a preferred substrate, they have been shown to work most efficiently towards glyoxylate. Their secondary substrates include hydroxypyruvate, phenylpyruvate and pyruvate, but not 2-keto-ᴅ-gluconate, as for several GHRB members.