Digestion of spinach chloroplasts with pancreatic lipase or trypsin effectively uncoupled electron transport. Continued digestion led to inhibition of saturated rates of Hill reaction activity and a decrease in quantum yield. Irradiation with ultraviolet light decreased the quantum yield and inhibited Hill activity, but did not uncouple. Ascorbate-dichlorophenol-indophenol-mediated reduction of...

This study was supported in part by Research Crane B-621 from the National Institute of Neurological Diseases and Blindness, National Institutes of Health, Bethesda, Md. all experiments. Ouabain was given intravenously in doses of 100 to 250 meg. per kilogram or by injection into the vitreous of one eye (0.1 meg. ouabain in 10 to 20 meg. of distilled water), lntravitreal injections were perform...

course similar to that of the other tissues during the first 8-10 days, but after that time until the premortal stage a residue persists which gives the Roe & Kuether reaction and which reduces indophenol. 5. Scurvy develops in guinea-pigs when the curve of the ascorbic acid tissue concentration reaches asymptotic values for long periods of depletion, and there is no definite correlation betwee...

It is well known that the determination of ascorbic acid in urine by titration with 2,6dichlorophenol indophenol in acid solution is not a specific method. Various interfering substances have been reported, such as sulfhydryl compounds (l), thiosulfate (2), and pyridium (medication) (3). The same limitations apply to other oxidation-reduction methods, except when the reducing substance is deter...

Low-dimensional cuprous nitride (Cu3N) was synthesized by nitridation (ammonolysis) of cuprous oxide (Cu2O) nanocrystals using either ammonia (NH3) or urea (H2NCONH2) as the nitrogen source. The resulting nanocrystalline Cu3N spontaneously decomposes to nanocrystalline CuO in the presence of both water and oxygen from air at room temperature. Ammonia was produced in 60% chemical yield during Cu...

A sensitive, optimized assay for serum AMP deaminase (EC 3.5.4.6) is presented, which is based on a colorimetric indophenol determination of ammonia liberated during the enzyme reaction. An average enzyme activity in serum of 2.7 U/liter (n = 36, range 0-6.2) for healthy adults was established. Both the enzyme and colorimetric reactions were optimized to give an assay sensitivity of 0.2 U/liter...

Changes in the intensity of the electron spin resonaince signal of divalent manganese were found to occur in suspensions of wild-type Chlamydamonas reinhardi. The dbserved manganese signal decreased in the light and increased in the dark. Through the use of a continuous-flow system it was possiible to determlline that the manganous ions responsible for the observed, signal were localized solely...

1. ARNON, D. I. Copper enzymes in isolated chloroplasts. Polyphenol oxidase in Beta uulgaris. Plant Physiol. 24: 1-15. 1949. 2. ARNON, D. I., ALLEN, M. B., and WHATLEY. F. R. Photosynthesis by isolated chloroplasts. IV. General concept and comparison of three photochemical reactions. Biochim. Biophys. Acta 20: 449-461. 1956. 3. ARNON, D. I., WHATLEY, F. R. and ALLEN, M. B. Assimilatory power in...

A carbohydrate:acceptor oxidoreductase from Paraconiothyrium sp. was purified and characterized. The enzyme efficiently oxidized -(1!4) linked sugars, such as lactose, xylobiose, and cellooligosaccharides. The enzyme also oxidized maltooligosaccharides, D-glucose, D-xylose, D-galactose, L-arabinose, and 6-deoxy-D-glucose. It specifically oxidized the -anomer of lactose. Molecular oxygen and 2,6...