this article addresses the interplay between heat of hydration and physico-mechanical properties of calcium sulfate hemi-hydrate in the presence of retarding additives such as citric and malic acids and sodium citrate. the heat of hydration was measured using a semi-isothermal calorimeter. results proved that citric and malic acids had superior impact on hydration and mechanical properties. whi...

The dicarboxylic acid malic acid synthesized as part of the tricarboxylic acid cycle can be produced in excess by certain microorganisms. Although malic acid is produced industrially to a lesser extent than citric acid, malic acid has industrial applications in foods and pharmaceuticals as an acidulant among other uses. Only recently has the production of this organic acid from coproducts of in...

Insufficient wine acidity can affect wine quality and stability. To overcome this problem, DL-malic acid can be added to the grape juice prior to fermentation. We have investigated the effect of DL-malic acid on wine fermentations and its influence on the final concentration of L-malic acid, naturally present in grape juice. To this end yeast strains that metabolise L-malic acid in different wa...

Malic enzyme [L-malate: NAD(P)(+) oxidoreductase (EC 1.1.1.39)] catalyzes the oxidative decarboxylation of L-malic acid to produce pyruvic acid using the oxidized form of NAD(P) (NAD(P)(+)). We used a reverse reaction of the malic enzyme of Pseudomonas diminuta IFO 13182 for HCO(3)(-) fixation into pyruvic acid to produce L-malic acid with coenzyme (NADH) generation. Glucose-6-phosphate dehydro...

Phosphoenolpyruvate (PEP) carboxylase activity in immature ;Carignane' grape berries (Vitis vinifera L.) had a temperature optimum of about 38 C, whereas malic enzyme activity rose with increasing temperature between 10 and 46 C. In vitro temperature inactivation rates for the PEP carboxylase were markedly greater than for the malic enzyme activity. From the simultaneous action of malic acid-pr...

This article addresses the interplay between heat of hydration and physico-mechanical properties of calcium sulfate hemi-hydrate in the presence of retarding additives such as citric and malic acids and sodium citrate. The heat of hydration was measured using a semi-isothermal calorimeter. Results proved that citric and malic acids had superior impact on hydration and mechanical properties. Whi...

Photosynthetic gas exchange and malic acid fluctuations were monitored in 69 well-watered plants from five morphologically similar species of Talinum in an investigation of the ecophysiological significance of the Crassulacean acid metabolism (CAM)-cycling mode of photosynthesis. Unlike CAM, atmospheric CO(2) uptake in CAM-cycling occurs exclusively during the day; at night, the stomata are clo...

Antisera prepared against two isologous malic enzymes from Lactobacillus casei strains 64H and M40 were used to survey and categorize the various malic enzymes found within this diverse species. In addition to detecting three major antigenic variants of malic enzyme within this group, both antisera readily reacted with Streptococcus faecalis malic enzyme. The cross-reactions between the L. case...

1. Cell-free extracts from culture epimastigotes of Trypanosoma cruzi contained two forms of NADP+-linked 'malic' enzyme (EC 1.1.1.40), I and II, with the same molecular weight but different electrophoretic mobilities and kinetic and regulatory properties. 2. The apparent Km for L-malate was lower for 'malic' enzyme I, with hyperbolic kinetics, whereas the kinetic pattern for 'malic' enzyme II ...

We investigated the role of organic acids in conferring Al tolerance in near-isogenic wheat (Triticum aestivum L.) lines differing in Al tolerance at the Al tolerance locus (Alt1). Addition of Al to nutrient solutions stimulated excretion of malic and succinic acids from roots of wheat seedlings, and Al-tolerant genotypes excreted 5- to 10-fold more malic acid than Al-sensitive genotypes. Malic...