Nonspecific esterases and malate dehydrogenases of 1-5 females from 40 root-knot nematode populations from Portugal were analyzed by electrophoresis in 0.4-mm-thick polyacrylamide gels. Fourteen major bands of esterase activity were detected, corresponding to 10 distinct phenotypes, Meloidogyne javanica and M. hapla had distinct species-specific phenotypes. Two phenotypes occurred in M. arenari...

The stereospecificity of the chicken heart mitochondrial malate dehydrogenase as well as the ability of this enzyme to form various abortive complexes has been further investigated. The enzyme was found to be specific for the A-hydrogen of NADH. Complex formation of the enzyme with oxalacetate and oxidized coenzymes is pH-dependent and is promoted at alkaline pH values. The enol form of oxalace...

Seven untrained volunteers [3 men, 4 women, 20.1 +/- 2.0 (SD) yr, 66. 0 +/- 11.0 kg, 171 +/- 13 cm] participated in a 10-day cycle exercise training program. Resting muscle samples were obtained from vastus lateralis before and after 5 and 10 days of training. Mitochondrial ATP production rate (MAPR) was assayed in isolated mitochondria by using a bioluminescence technique and referenced to the...

The effect of citrate on the structure and function of porcine heart mitochondrial malate dehydrogenase (EC 1.1.1.37) has been characterized. The native dimeric form of this enzyme is specifically activated by citrate in the NAD’ -+ NADH direction and inhibited by citrate in the NADH -+ NAD’ direction. It is proposed that citrate is bound at a regulatory site that is distinct from the catalytic...

Thiamin (vitamin B1) is a pharmacological agent boosting central metabolism through the action of the coenzyme thiamin diphosphate (ThDP). However, positive effects, including improved cognition, of high thiamin doses in neurodegeneration may be observed without increased ThDP or ThDP-dependent enzymes in brain. Here, we determine protein partners and metabolic pathways where thiamin acts beyon...

Recent studies in this laboratory have shown that porcine heart mitochondrial malate dehydrogenase (Lmalate:NAD* oxidoreductase, EC 1.1.1.37) exhibits both a concentration and a pH-dependent dissociation (Bleile, D. M., Schulz, R. A., Gregory, E. M., and Harrison, J. H. (1977) J. Biol. Chem. 252,756758; Hodges, C. T., Wiggins, J. C., and Harrison, J. H. (1977) J. BioZ. Chem. 252, 6038-6041). Si...

late: NAD oxidoreductase; EC 1.1.1.37) is an enzyme very commonly occurring in animals, plants and microorganisms. MDH catalyzes the oxidation (dehydration) of L-malate to oxaloacetate in the presence of NAD+ as a cofactor: This article is an overview of literature data on the structure, properties, functions and genetic control of the enzyme malate dehydrogenase (MDH) in plants. In most of the...

An attempt to isolate intact mitochondria from dry pea seeds (Pisum sativum var. Alaska) ended in failure. Cytochrome oxidase in crude mitochondrial fraction from dry seeds was separated into three fractions by sucrose density gradient centrifugation. Two of the fractions contained malate dehydrogenase, whereas the other did not. Equilibrium centrifugation of mitochondrial membrane on sucrose g...

Developmental downregulation of the malate-aspartate shuttle has been observed in cardiac mitochondria. The goals of this study were to determine the time course of the postnatal decline and to identify potential regulatory sites by measuring steady-state myocardial mRNA and protein levels of the mitochondrial proteins involved in the shuttle. By use of isolated porcine cardiac mitochondria inc...

During the course of studies on the effect of vitamin K on several respiratory chain enzymes from 1VIycobacterium phlei, it was found that the soluble fraction contained a unique enzyme which required vitamin K suspended in phospholipid for the reduction of thiazolyl blue tetrazolium by malate. Malate oxidation in most tissues is catalyzed by the classical pyridine nucleotide-linked malic dehyd...