<p>This family of proteins are annotated as either enolase-phosphatasesor putative enolase-phosphatases. </p><p>The methionine salvage pathway converts the methylthioribose moiety of 5'-(methylthio)-adenosine to methionine via a series of biochemical steps in a wide variety of organisms. One enzyme active in this pathway is a bifunctional enolase-phosphatase called E-1 that promotes oxidative cleavage of the synthetic substrate 2,3-diketo-1-phosphohexane to 2-keto-pentanoate; it has been purified from the Gram-negative bacterium <taxon tax_id="573">Klebsiella pneumoniae</taxon> [<cite idref="PUB00002812"/>]. The unusual metabolite 2,3-diketo-5-methylthio-1-phosphopentane is oxidatively cleaved to yield formate (from C-1), 2-keto-4-methylthiobutyrate (the transamination product of methionine), and 3-methylthiopropionate by E-1. The native enzyme is a monomeric protein of M(r) 27,000 requiring magnesium ion as a cofactor [<cite idref="PUB00002812"/>]. The cloning and analysis of E-1 from <taxon tax_id="571">Klebsiella oxytoca</taxon> has been reported [<cite idref="PUB00014767"/>].</p>