Nichtflüchtige Mono-, Di- und Tricarbonsäuren

Oxidation of Ethylene Glycol by a Salt-Requiring Bacterium

“…The absence of glycolate in the reaction mixture probably was the result of the more rapid rate of oxidation of glycolate. Extrapolating from the activity observed in the cell-free extracts, 0.65 ,ug of glycolate could be oxidized per h per mg of protein, whereas only 0.31 ,Ag of ethylene glycol could be oxidized per mg of protein per h. indicated by the characteristic formation of a red-to-orange color after the addition of phenylhydrazine, HCl, and K3Fe(CN)6 (16). Chromatography of the extracted 2,4-dinitrophenylhydrazine derivatives of compounds in the cell-free preparations yielded three radioactive spots.…”

“…Glycolate oxidase activity was higher in cells grown on ethylene glycol than in cells grown on glycerol (Table 2). Although the colorimetric procedure of Wolf (16) indicated that glyoxylate was present, neither glycolate nor glyoxylate was detected in the free-acid analysis of the reaction mixtures, but radioactive spots were detected which corresponded with glycine and serine. Glycine has been shown to occur as a secondary metabolite from metabolism of compounds in which glyoxylate was an intermediate (15), and the amination of glyoxylate to glycine followed by condensation to serine has been reported (14).…”

“…A reaction mixture containing 200 mg of protein (crude extract) in phosphate buffer (0.1 M, pH 7.2) and 200 ,umol of ethylene glycol with 5 ,uCi of [1,2-14C]ethylene glycol (ICN, Irvine, Calif.) was incubated at 30°C as described for cultures. Samples were periodically tested for the presence of glyoxylate by the colorimetric procedure of Wolf (16). When the concentration of glyoxylate reached 5 to 10 ,ug ml-', the reaction was stopped by quick freezing in liquid N2 (for analysis of free organic acids) or by addition of 4 g of (NaPO3)3.…”

Déficiences du métabolisme oxydatif et différenciation sexuelle chez Allomyces et Neurospora. Activité d’une DPN-deshydrogénase lactique chez Allomyces

“…Pour la détermination quantitative de l'acide lactique, une extraction â l'éther diéthylique des filtrats (15 ml) acidifiés fortement avec 1LSO, 2% a précédé le dosage titrimétrique des extraits (contre-titration à l'HCl 0,1 N de l'excès d 'une quantité connue de KOH 0.02 N ajoutée pour neutraliser l'acide lactique et traces d'autres acides organiques extraits). Ajoutons que chaque extrait éthéré a été séché sur Na2SO, anhydre pour réduire sa contamination par des traces d'acide minéral (Wolf, 1955).…”