Crane and Lipmann (1) have shown that arsenate uncouples oxidative phosphorylation in intact rat liver mitochondria, and that this effect can be reversed by phosphate. They postulated that arsenate competes with phosphate at the site of phosphate uptake. It has also been observed that arsenate can stimulate the respiration of intact mitochondria (1) and of submitochondrial particles’ in the abs...

Vesicles have been prepared by mild sonication of a purified inner membrane fraction from rat liver mitochondria. Such vesicles demonstrate an energy-dependent net concentrative uptake of inorganic phosphate in the absence of added Na+, Ca’+, or ionophores. Phosphate uptake can be supported by a variety of substrates including /?-hydroxybutyrate, succinate, and ascorbate + tetramethylphenylened...

In a previous communication (l), an accumulation of oxaloacetic acid was implicated as the cause of a decline of succinate oxidation in liver mitochondria from rats fed a diet deficient in vitamin E. This conclusion appeared justified from observations that compounds known to accelerate the removal of oxalo.acetate would relieve this decline of succinate oxidation. There was, however, a lack of...

Studies of isolated rat liver mitochondria were undertaken in order to evaluate the importance of glutamate transport, oxidation reduction state, and product inhibition on the rates of formation of ammonia from glutamate. Uptake and efflux of glutamate across the mitochondrial membrane were measured isotopically in the presence of rotenone. Efflux was stimulated by H+ in the mitochondrial matri...

Studies of isolated rat liver mitochondria were undertaken in order to evaluate the importance of glutama te transport, oxidation reduction state, and product inhibition on the rates of formation of ammonia from glutamate. Uptake and efflux of glutamate across the mitochondrial membrane were measured isotopically in the presence of rotenone. Efflux was stimulated by H+ in the mitochondrial matr...

1. Rat-liver mitochondria showed a decrease in amino acid production after preparation in 0-25m-sucrose containing EDTA (lnm), but an increase in water content. When EDTA was replaced by Mn2+ (Imm) or succinate (lmM), both amino acid production and water content were lowered, whereas preparation in 0-9% potassium chloride caused an increase in both. 2. Amino acid production by rat-liver homogen...

L-threonine dehydrogenase (E.C.1.1.1.103) catalyzes the NAD+-dependent transformation of Lthreonine to 2-amino 3-0x0-butyric acid, which spontaneously loses CO2 with the final production of aminoacetone ( 1) The enzyme is present in several microorganisms as well as in the liver of vertebrates (2-6). We studied some properties of the rat liver enzyme, showing that the activity was strongly inhi...

Evidence is given indicating that the outer membrane of mitochondria from AH-130 Yoshida ascites hepatoma has low resistance to trypsin. The outer membrane of freshly-isolated hepatoma mitochondria is impermeable to cytochrome c and dextran, but it seems to be easily digested by trypsin. The proteolytic enzyme partially inactivates the adenylate kinase and cytochrome c oxidase of these mitochon...

The electron microscope has been used to determine the weight distribution of isolated subcellular particles from normal rat liver. The following results are reported: (1) There exist at least two well defined weight populations of subcellular particles; their respective median weights are 1.3 x 10(-14) and 11 x 10(-14) gm. The lighter fraction is considered to consist of lysosomes, the heavier...

fienoniycin is a new polyene antibiotic produced by Actinomyces distatochromogenes var. lienomycini, exhibiting antifungal, antibacterial and antitumor activity [l-4] . It changes the plasma membrane permeability characteristics of sensitive organisms [5] . The present report deals with so far unobserved sensitivity of rat-liver mitochondria to lienomycin. The antibiotic stimulates mitochondria...