title: Glycine formation during growth of Pseudomonas AM1 on methanol and succinate.
abstract: 1. The mechanism of regeneration of glycine during the growth of Pseudomonas AM1 on C(1) compounds has been investigated by brief incubation of bacterial suspensions with [2,3-(14)C(2)]succinate and observing the incorporation of radioactivity into various metabolites. 2. With the wild-type organism growing on methanol, radioactivity appeared rapidly in glycine and tricarboxylic acid-cycle intermediates, but there was a relatively slow labelling of serine and phosphorylated compounds. Serine became labelled predominantly in the C-2 position. 3. The proportion of radioactivity incorporated into glycine at earliest times was greatly diminished when succinate-grown cells were used. 4. Radioactivity was also incorporated from [2,3-(14)C(2)]succinate into glycine and serine by methanol-grown mutant 20S, which lacks phosphoserine phosphohydrolase. Both the glycine and serine were labelled mainly in C-2. 5. The formation of predominantly [2-(14)C]serine from [2,3-(14)C(2)]succinate in wild-type Pseudomonas AM1, and of [2-(14)C]serine and [2-(14)C]glycine in the mutant lacking the phosphorylated pathway from succinate to serine, is taken as strong evidence for a mechanism of glycine regeneration involving cleavage of a C(4) skeleton between C-2 and C-3, rather than by a direct combination of two C(1) units derived from the growth substrate. 6. The cleavage mechanism is quantitatively more significant during growth on methanol than on succinate.
mesh_terms: D002247:Carbon Isotopes; D002845:Chromatography; D002952:Citric Acid Cycle; D005998:Glycine / Q000096:biosynthesis* / Q000378:metabolism; D000432:Methanol / Q000378:metabolism*; D010744:Phosphoric Monoester Hydrolases; D011549:Pseudomonas / Q000254:growth & development / Q000378:metabolism*; D012694:Serine / Q000378:metabolism; D013386:Succinates / Q000378:metabolism*
chemical_list: D002247:Carbon Isotopes; D013386:Succinates; D012694:Serine; D010744:Phosphoric Monoester Hydrolases; D005998:Glycine; D000432:Methanol