title: Isoform expression in the multiple soluble malate dehydrogenase of Hoplias malabaricus (Erythrinidae, Characiformes).
abstract: Kinetic properties and thermal stabilities of Hoplias malabaricus liver and skeletal muscle unfractionated malate dehydrogenase (MDH, EC 1.1.1.37) and its isolated isoforms were analyzed to further study the possible sMDH-A* locus duplication evolved from a recent tandem duplication. Both A (A1 and A2) and B isoforms had similar optima pH (7.5-8.0). While Hoplias A isoform could not be characterized as thermostable, B could as thermolabile. A isoforms differed from B isoform in having higher Km values for oxaloacetate. The possibly duplicated A2 isoform showed higher substrate affinity than the A1. Hoplias duplicated A isoforms may influence the direction of carbon flow between glycolisis and gluconeogenesis.
authors.affiliation: Universidade do Vale do Paraíba, FEAU, Avenida Shishima Hifumi, 2911, CEP 12010-400, São José dos Campos, SP, Brazil. mreginaquino@aol.com
authors.forename: M R
authors.initials: MR
authors.lastname: Aquino-Silva
authors.forename: M L
authors.initials: ML
authors.lastname: Schwantes
authors.forename: A R
authors.initials: AR
authors.lastname: Schwantes
mesh_terms: D000818:Animals; D004592:Electrophoresis, Starch Gel; D005399:Fishes / Q000235:genetics* / Q000378:metabolism; D020440:Gene Duplication; D006863:Hydrogen-Ion Concentration; D007527:Isoenzymes / Q000235:genetics*; D007700:Kinetics; D008291:Malate Dehydrogenase / Q000235:genetics* / Q000302:isolation & purification; D013696:Temperature
chemical_list: D007527:Isoenzymes; D008291:Malate Dehydrogenase