Cells isolated from the livers of 17- to 19-day-old chick embryos were maintained in a chemically defined culture medium. During 3 days in culture the activity of malic enzyme, a measure of its concentration, was stimulated 2-, 23-, or 77-fold by insulin, triiodothyronine, or insulin plus triiodothyronine, respectively. Glucagon blocked the stimulation caused by insulin plus triiodothyronine. C...

This work evaluated the effect of malic acid washing on the growth of Listeria monocytogenes on poultry legs stored at 4°C for 8 d. Fresh inoculated chicken legs were dipped into a 1 or 2% malic acid solution (vol/vol) for 5 min or distilled water (control). Surface pH values, sensorial characteristics (odor, color, texture, and overall appearance) and L. monocytogenes, mesophile, psychrotroph,...

A complete chemical balance which demonstrates the occurrence of Reaction 3 has now been obtained. There is no reaction in the absence of either TPN, .Zwischenferment, or “malic” enzyme. The rate of reaction is proportional to the concentration of “malic” enzyme and to the CO* tension. It is also possible to couple the isocitric dehydrogenase-oxalosuccinic carboxylase system (2) with “malic” en...

DL-Malic acid-grown cells of the yeast Hansenula anomala formed a saturable transport system that mediated accumulative transport of L-malic acid with the following kinetic parameters at pH 5.0: Vmax, 0.20 nmol.s-1.mg (dry weight)-1; Km, 0.076 mM L-malate. Uptake of malic acid was accompanied by proton disappearance from the external medium with rates that followed Michaelis-Menten kinetics as ...

After preparation on self-generated Percoll gradients, avocado (Persea americana Mill, var. Fuerte and Hass) mitochondria retain a high proportion of cyanide-insensitive respiration, especially with alpha-ketoglutarate and malate as substrates. Whereas alpha-ketoglutarate oxidation remains unchanged, the rate of malate oxidation increases as ripening advances through the climacteric. An enhance...

Malic enzymes are widely distributed in nature, and have important biological functions. They catalyze the oxidative decarboxylation of malate to produce pyruvate and CO(2) in the presence of divalent cations (Mg(2+), Mn(2+)). Most malic enzymes have a clear selectivity for the dinucleotide cofactor, being able to use either NAD(+) or NADP(+), but not both. Structural studies of the human mitoc...

Schizosaccharomyces pombe is of interest to wine-makers because, unlike the Saccharomyces cerevisiae wine yeasts, it eciently metabolizes all levels of malic acid found in grape musts. To determine the metabolic pathway for malatemetabolism in Sch. pombe, a mutational analysis was performed using a selection system which isolated 154mutants that were unable to utilize malic acid. Themutants we...