The gene encoding the tetrameric malate dehydrogenase (MDH) in a thermophilic Bacillus species (BI) has been cloned in an Escherichia coli plasmid. The nucleotide sequence of the gene, the first to be elucidated for a tetrameric MDH, shows the MDH subunit to contain 312 amino acids and have a molecular mass of 33648 Da, which confirms the experimentally determined value of about 35 kDa. Like th...

Several plants, fungi, algae, and certain bacteria produce mannitol, a polyol derived from fructose. Mannitol has multiple industrial applications in the food, pharmaceutical, and medical industries, being mainly used as a non-metabolizable sweetener in foods. Many heterofermentative lactic acid bacteria synthesize mannitol when an alternative electron acceptor such as fructose is present in th...

Like many other bacteria, Corynebacterium glutamicum possesses two types of L-malate dehydrogenase, a membrane-associated malate:quinone oxidoreductase (MQO; EC 1.1.99.16) and a cytoplasmic malate dehydrogenase (MDH; EC 1.1.1.37) The regulation of MDH and of the three membrane-associated dehydrogenases MQO, succinate dehydrogenase (SDH), and NADH dehydrogenase was investigated. MQO, MDH, and SD...

1. An isoenzymatic study on Schistosoma mansoni from Guadeloupe has been carried out using isoelectric focusing in polyacrylamide gels. 2. Among the seven systems examined (LDH, MDH, G6PD, PGI, PGM, AcP, HK), only MDH showed variation at the MDH-1 locus and mdh-1a allele frequencies were used to characterise eight strains derived either from human or murine hosts, and representative of differen...

Malate dehydrogenase (MDH) plays important metabolic roles in bacteria. In this study, the recombinant MDH protein (His-MDH) of Brucella abortus was purified and its ability to catalyze the conversion of oxaloacetate (OAA) to L-malate (hereon referred to as MDH activity) was analyzed. Michaelis Constant (Km) and Maximum Reaction Velocity (Vmax) of the reaction were determined to be 6.45 × 10(-3...

The quinoprotein methanol dehydrogenase (MDH) contains a Ca2+ ion at the active site. Ca(2-)-free enzyme (from a processing mutant) was used to obtain enzyme containing Sr2+ or Ba2+, the Ba(2+)-MDH being the first enzyme to be described in which a Ba2+ ion functions at the active site. The activation energy for oxidation of methanol by Ba(2+)-MDH is less than half that of the reaction catalysed...

The activity of Drosophila cytosolic malate dehydrogenase (MDH; EC 1.1.1.40), a key enzyme in the biosynthesis of lipids, was found to be regulated by both the sesquiterpenoid juvenile hormone (JH), and the steroid hormone ecdysone. The responsiveness of MDH to JH largely depended on the developmental stage or endogenous titre of ecdysone. During the early through middle period of the last larv...

In the initial steps of their metabolic pathway, methanotrophic bacteria oxidize methane to methanol with methane monooxygenases (MMOs) and methanol to formaldehyde with methanol dehydrogenases (MDHs). Several lines of evidence suggest that the membrane-bound or particulate MMO (pMMO) and MDH interact to form a metabolic supercomplex. To further investigate the possible existence of such a supe...

Light-induced swelling of guard cell protoplasts (GCP) from Vicia faba was accompanied by increases in content of K(+) and malate. DCMU inhibited the increase of K(+) and malate, and consequently swelling.Effect of light on the activity of selected enzymes that take part in malate formation was studied. When isolated GCP were illuminated, NADP-malate dehydrogenase (NADP-MDH) was activated, and ...

Transposon mutagenesis and antibiotic enrichment were employed to isolate a mutant of Rhodobacter sphaeroides Si4 designated strain M22, that had lost the ability to grow on D-mannitol and to produce the enzyme mannitol dehydrogenase (MDH). DNA flanking the transposon in the mutant strain was used as a probe for the identification and cloning of the MDH gene (mtlK). A 5.5 kb EcoRI/BglII fragmen...