title: Two glyceraldehyde-3-phosphate dehydrogenase isozymes from the koningic acid (heptelidic acid) producer Trichoderma koningii.
abstract: The sesquiterpene lactone koningic acid (heptelidic acid) irreversibly inactivated glyceraldehyde-3-phosphate dehydrogenase [D-glyceraldehyde 3-phosphate: NAD+ oxidoreductase (phosphorylating)] (EC 1.2.1.12) (GAPDH) and thus inhibits glycolysis. The koningic-acid-producing strain of Trichoderma koningii M3947 was shown to contain the koningic-acid-resistant GAPDH isozyme (GAPDH I) under conditions of koningic acid production. In peptone-rich medium, however, no koningic acid production was observed, and the koningic-acid-sensitive GAPDH isozyme (GAPDH II), in addition to the resistant enzyme, was produced. Both enzymes were tetramer with a molecular mass of 152 kDa (4 x 38 kDa) and lost enzyme activity when two of the four cysteine residues reacted with koningic acid. The apparent Km values of GAPDH I and II for glyceraldehyde 3-phosphate were 0.54 mM and 0.33 mM, respectively. The former isozyme was inhibited 50% by 1 mM koningic acid but not affected at 0.1 mM, while the latter isozyme was inhibited 50% at 0.01 mM. The immunochemical properties and partial amino acid sequences suggested that the two isozymes have different molecular structures. These results suggest that GAPDH I is responsible for the glycolysis in T. koningii when koningic acid is produced.
authors.affiliation: Department of Applied Biological Science, Tokyo Noko University, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Sakai
authors.forename: K
authors.initials: K
authors.lastname: Hasumi
authors.forename: A
authors.initials: A
authors.lastname: Endo
mesh_terms: D000595:Amino Acid Sequence; D004228:Dithionitrobenzoic Acid / Q000737:chemistry; D005285:Fermentation; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000302:isolation & purification*; D007527:Isoenzymes / Q000302:isolation & purification; D007700:Kinetics; D008969:Molecular Sequence Data; D015394:Molecular Structure; D008970:Molecular Weight; D012717:Sesquiterpenes / Q000378:metabolism / Q000494:pharmacology; D014242:Trichoderma / Q000201:enzymology*
chemical_list: D007527:Isoenzymes; D012717:Sesquiterpenes; C027285:heptelidic acid; D004228:Dithionitrobenzoic Acid; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases