Presence Of 3-mercaptopropionic Acid Research Articles

Novel precursor substrates for polythioesters (PTE) and limits of PTE biosynthesis in Ralstonia eutropha

A novel class of biopolymers referred to as polythioesters (PTE) was recently detected when the polyhydroxyalkanoate (PHA) accumulating bacterium Ralstonia eutropha was cultivated in the presence of 3-mercaptopropionic acid (3MP) or 3,3′-thiodipropionic acid (TDP). In this study, 3,3′-dithiodipropionic acid (DTDP) and 3-mercaptovaleric acid (3MV) were identified as two additional precursor carbon sources for in vivo biosynthesis of PTE in R. eutropha. Biosynthesis of copolymers of 3-hydroxybutyrate (3HB) and 3MP, which contributed 19–25% of cell dry matter, was compared referring to the different precursor substrates. Using DTDP as carbon source, which is probably cleaved into two molecules 3MP, yielded an about 2.3-fold higher molar 3MP content of the copolyester than TDP, which is probably cleaved into only one molecule 3MP. Furthermore, cultivation of R. eutropha in the presence of 3MV resulted in biosynthesis of copolymers consisting predominantly of 3HB with low amounts of 3MV and 3-hydroxyvalerate, each contributing less than 5 mol% of the constituents. In contrast, 4-mercaptobutyric acid could be not incorporated into PHAs, although – as documented in this study – five different strategies, various precursor substrates, R. eutropha and also a recombinant strain of Escherichia coli were employed. Therefore, this study not only extended the range of substrates suitable for PTE biosynthesis and also the range of PTE constituents in R. eutropha, it also demonstrates limits for PTE biosynthesis in this bacterium.

Preparation of Luminescent Polyelectrolyte/Cu-Doped ZnSe Nanoparticle Multilayer Composite Films

ZnSe and Cu-doped ZnSe nanoparticle aqueous suspensions were prepared in the presence of mercaptopropionic acid (MPA). Cu-doped ZnSe nanoparticles exhibited a strong blue emission that was strongly dependent upon the Cu dopant level and the chemical surface passivation produced by zinc–mercaptopropionic acid complexes. These Cu-doped ZnSe nanoparticles were further assembled into ultrathin polymer-supported films using electrostatic interactions and the layer-by-layer assembly method. UV–visible spectroscopy and X-ray photoelectron spectroscopy (XPS) provided evidence for the presence and optical activity of Cu-doped ZnSe nanoparticles within the polymer ultrathin films. Moreover, XPS data supported the presence of zinc mercaptopropionic acid complexes on nanoparticle surfaces and the presence of Cu+ ions with high luminescent activity in the doped nanoparticles.

Antibacterial biopolymers

A new class of polythioester (PTE) biopolymer has been developed at the University of Münster, Germany, which could reduce the rate of post-operative infections in surgical implants (Microbiology, 147). Led by Alexander Steinbüchel, researchers grew the bacterium Ralstonia eutropha in the presence of 3-mercaptopropionic acid or 3,3′-thiodipropionic acid as a carbon source, in addition to fructose and glucoronic acid, and produced a 3-hydroxy butyrate/3-mercaptopropionate co-polymer – the first bacterially produced polymer to contain sulfur in the backbone. The inherent anti-bacterial properties of the biopolymers means that they will have significant advantages over hydrocarbon-based polymers, which are susceptible to bio-fouling which can cause inflammation of surrounding tissue and infection. M.J.D.

Metabolism of paeoniflorin and related compounds by human intestinal bacteria. IV. Formation and structures of adducts of a metabolic intermediate with sulfhydryl compounds by Lactobacillus brevis.

Paeoniflorin from peony roots was converted to new compounds in the presence of various sulfhydryl compounds by Lactobacillus brevis. The compounds formed in the presence of 3-mercaptopropionic acid, 2-mercaptoethanol and thiobenzoic acid were determined to be 7R and 7S mixture of 8-(2-carboxyethylthio)paeonimetabolin I, 8-(2-hydroxyethylthio)paeonimetabolin I and 8-benzoylthiopaeonimetabolin I, respectively, by various spectroscopic methods. These compounds are adducts of a metabolic intermediate of paeoniflorin with the sulfhydryl compounds.

Polarographic Reduction of Tin(IV) in the Presence of 3-Mercaptopropionic Acid.

Polarographic Reduction of Tin(IV) in the Presence of 3-Mercaptopropionic Acid.