Ferrous- or cobalt ion-dependent D-(-)-tartrate dehydratase of pseudomonads: purification and properties

Abstract

D-(-)-Tartrate dehydratases [D-(-)-tartrate hydro-lyase, EC 4.2.1...] were isolated from two Pseudomonas strains. The molecular weights of the native enzymes were determined to be 72,000 and 78,000, respectively, and each enzyme was composed of two subunits of identical size. The dehydratases had no requirements for thiol compounds, were insensitive to oxygen, and required Fe2+ (0.1 mM) or Co2+ (0.5 mM) ions for optimal activity.

Iron−Sulfur Proteins with Nonredox Functions

“…d -(+)-Tartrate dehydratase from a Pseudomonas species requires either iron or cobalt for activity but does not require a thiol compound for activation. It seems doubtful that either of these enzymes contains a Fe-S cluster …”

“…A cluster of the rubredoxin type would be consistent with the presence of one iron per mole of protein, but no optical spectra typical of a rubredoxin-like iron center have been reported for these proteins. Pseudomonas d -(+)-tartrate dehydratase resembles these four enzymes in requiring a divalent cation for activity but lacking a Fe-S cluster. , …”

“…Pseudomonas D-(+)-tartrate dehydratase resembles these four enzymes in requiring a divalent cation for activity but lacking a Fe-S cluster. 72,73 dratases catalyze the removal of water from their substrates by a syn elimination. 104,105 An enlightening review of these reactions has been written by Buckel and his colleagues.…”

Occurrence of a New Enzyme,meso-Tartrate Dehydratase ofPseudomonas putida

“…This method was used throughout, unless otherwise specified. Method B: the production of oxalacetate was followed at 340 nm using a coupled assay system with malate dehydrogenase and NADH as described by Rode and Giffuorn 4 ) under anaerobic conditions.…”

Adaptation of Rhodopseudomonas sphaeroides to Growth on d -(—)-Tartrate and Large-Scale Production of a Constitutive d -(—)-Tartrate Dehydratase During Growth on dl -Malate

“…Growth on D-(-)-tartrate has been reported for enterobacteria (1,4,24), pseudomonads (7,9,(19)(20)(21), and Rhodopseudomonas sphaeroides (18). For R. sphaeroides (18) and two Pseudomonas strains (19), it has been shown that this compound is metabolized by highly specific D-(-)-tartrate dehydratases.…”