Characterization of two glyceraldehyde-3-phosphate dehydrogenase isoenzymes from the pentalenolactone producer Streptomyces arenae.
Pentalenolactone (PL) irreversibly inactivates the enzyme glyceraldehyde-3-phosphate dehydrogenase [D-glyceraldehyde-3-phosphate:NAD+ oxidoreductase (phosphorylating)] (EC 1.2.1.12) and thus is a potent inhibitor of glycolysis in both procaryotic and eucaryotic cells. We showed that PL-producing strain Streptomyces arenae TU469 contains a PL-insensitive glyceraldehyde-3-phosphate dehydrogenase under conditions of PL production. In complex media no PL production was observed, and a PL-sensitive glyceraldehyde-3-phosphate dehydrogenase, rather than the insensitive enzyme, could be detected. The enzymes had the same substrate specificity but different catalytic and molecular properties. The apparent Km values of the PL-insensitive and PL-sensitive enzymes for glyceraldehyde-3-phosphate were 100 and 250 microM, respectively, and the PL-sensitive enzyme was strongly inhibited by PL under conditions in which the PL-insensitive enzyme was not inhibited. The physical properties of the PL-insensitive enzyme suggest that the protein is an octamer, whereas the PL-sensitive enzyme, like other glyceraldehyde-3-phosphate dehydrogenases, appears to be a tetramer.
D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000302:isolation & purification / Q000378:metabolism*; D007527:Isoenzymes / Q000302:isolation & purification / Q000378:metabolism*; D007700:Kinetics; D007783:Lactones / Q000096:biosynthesis / Q000494:pharmacology; D046911:Macromolecular Substances; D008970:Molecular Weight; D012717:Sesquiterpenes; D013302:Streptomyces / Q000201:enzymology*
D007527:Isoenzymes; D007783:Lactones; D046911:Macromolecular Substances; D012717:Sesquiterpenes; C017996:arenaemycin E; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases