Thermal Effects on Kinetic Properties of NADP + -Malate Dehydrogenase in Two Ecotypes of the C 4 Grass Weed Echinochloa crus-galli (L.) Beauv. from Sites of Contrasting Climates

1989 ◽  
Vol 3 (6) ◽  
pp. 709 ◽  
Author(s):  
L. Lapointe ◽  
M. Dubuc ◽  
F. Vairinhos ◽  
J.-P. Simon
Keyword(s):  
Malate Dehydrogenase ◽  
Thermal Effects ◽  
Kinetic Properties ◽  
Grass Weed

scholarly journals Isoform expression in the multiple soluble malate dehydrogenase of Hoplias malabaricus (Erythrinidae, Characiformes)

2003 ◽  
Vol 63 (1) ◽  
pp. 7-15 ◽  
Author(s):  
M. R. Aquino-Silva ◽  
M. L. B. Schwantes ◽  
A. R. Schwantes
Keyword(s):  
Skeletal Muscle ◽  
Malate Dehydrogenase ◽  
Tandem Duplication ◽  
Carbon Flow ◽  
Substrate Affinity ◽  
Kinetic Properties ◽  
Thermal Stabilities ◽  
Hoplias Malabaricus ◽  
Isoform Expression

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.

Adaptation and acclimation of higher plants at the enzyme level: thermal properties of NAD malate dehydrogenase of two species of Aster (Asteraceae) and their hybrid adapted to contrasting habitats

1980 ◽  
Vol 58 (13) ◽  
pp. 1474-1481 ◽  
Author(s):  
Luc Brouillet ◽  
Jean-Pierre Simon
Keyword(s):  
Malate Dehydrogenase ◽  
Higher Plants ◽  
Enzyme Level ◽  
Leaf Tissue ◽  
Forest Understory ◽  
Kinetic Properties ◽  
Peptidase Activity ◽  
Crude Extracts ◽  
Contrasting Habitats ◽  
Sphagnum Bog

Thermal and kinetic properties of NAD malate dehydrogenase (MDH) were investigated in clonal populations of two species of Aster and their hybrid: A. acuminatus, a forest understory species; A. nemoralis, a sphagnum-bog species; and A. blakei, their hybrid occurring at the bog–forest ecotone. The populations were collected within a 300 m radius in southwestern Quebec. Compared with A. acuminatus, the MDH of crude extracts from A. nemoralis had lower thermostability in both 5- and 10-min assays at 55 °C, and reduced apparent energy of activation (Ea) in the temperature range of 15–25 °C. However, these differences were not maintained in purified extracts of the species and may be attributed to higher phenolase and peptidase activity in crude extracts of A. nemoralis. The ratio of MDH activity over total protein concentration, or fresh weight leaf tissue, was higher in A. acuminatus than in A. nemoralis. Most values for these MDH properties of A. blakei were intermediate between those of the two parents. No differences, however, were observed for the substrate binding ability (Km) of MDH in the three taxa. Electrophoretic analyses show no qualitative differentiation in the enzyme profiles of MDH of the three taxa, which consist of two mitochondrial and six cytosolic isozymes. Mitochondrial isozymes were more thermostable but no differences in thermostability were observed among the forms of the species. The thermal and kinetic properties of malate dehydrogenase, as measured in situ, have not been substantially modified by the contrasting microclimatic regimes associated with the habitats of A. acuminatus and A. nemoralis.

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