Isoform expression in the multiple soluble malate dehydrogenase of Hoplias malabaricus (Erythrinidae, Characiformes).
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.
Aquino-Silva
M R
MR
Universidade do Vale do Paraíba, FEAU, Avenida Shishima Hifumi, 2911, CEP 12010-400, São José dos Campos, SP, Brazil. mreginaquino@aol.com
Schwantes
M L
ML
Schwantes
A R
AR
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
D007527:Isoenzymes; D008291:Malate Dehydrogenase