title: Oxygen utilization by Lactobacillus plantarum. II. Superoxide and superoxide dismutation.
abstract: Cell-free extracts of Lactobacillus plantarum contain non-proteinaceous compounds which mimic superoxide dismutase activity. Using the test system in which O-2 is generated by xanthine oxidase, superoxide dismutase activity is found in cell-free extracts, where proteins are removed by precipitation. This activity is strongly decreased after dialysis of cell-free extracts. Superoxide dismutase activity was also investigated by means of pulse radiolysis. Cell-free extracts of Escherichia coli were also investigated as a comparison, which were known to contain superoxide dismutase. With cell-free extracts of both L. plantarum and E. coli the decay of O-2 was markedly increased. However, the type of reaction of the O-2 decay was of first order in the presence of E. coli extracts due to superoxide dismutase(s), and of second order in the presence of L. plantarum extracts, indicating that O-2 elimination is not an enzymic reaction. Mn2+ phosphate(s) might be responsible for the observed elimination of O-2. The production of O-2 is not detectable during NADH-, lactate- or pyruvate oxidase reactions in L. plantarum extracts.
mesh_terms: D002474:Cell-Free System; D007773:Lactates / Q000378:metabolism; D007778:Lactobacillus / Q000201:enzymology / Q000378:metabolism*; D008345:Manganese / Q000494:pharmacology; D009243:NAD / Q000378:metabolism; D010101:Oxygen Consumption; D011773:Pyruvates / Q000378:metabolism; D013482:Superoxide Dismutase / Q000378:metabolism*; D013481:Superoxides / Q000378:metabolism
chemical_list: D007773:Lactates; D011773:Pyruvates; D009243:NAD; D013481:Superoxides; D008345:Manganese; D013482:Superoxide Dismutase