title: Growth of Paracoccus denitrificans on [2,3-13C]succinate and [1,4-13C]succinate. II. Isoleucine biosynthesis.
abstract: Paracoccus denitrificans was grown on either [2,3-13C]succinate or [1,4-13C]succinate, and extracts were analysed by using gas chromatography-mass spectrometry. The distribution of label in isoleucine indicated that the 2-ketobutyrate required for isoleucine biosynthesis was mainly produced from pyruvate by 2-keto-acid chain elongation (i.e. the 'pyruvate elongation pathway'). Approximately 10% of isoleucine was produced by a second pathway involving propionyl CoA. Threonine and glutamate were not utilized by P. denitrificans as a source of 2-ketobutyrate production for isoleucine biosynthesis under the growth conditions used.
mesh_terms: D002247:Carbon Isotopes; D008401:Gas Chromatography-Mass Spectrometry; D007532:Isoleucine / Q000096:biosynthesis*; D007553:Isotope Labeling / Q000379:methods; D010231:Paracoccus denitrificans / Q000254:growth & development / Q000378:metabolism*; D013386:Succinates / Q000378:metabolism*
chemical_list: D002247:Carbon Isotopes; D013386:Succinates; D007532:Isoleucine