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Electron-paramagnetic-resonance studies of leghaemoglobins from soya-bean and cowpea root nodules. Identification of nitrosyl-leghaemoglobin in crude leghaemoglobin preparations.

ABSTRACT: 1. Leghaemoglobins from soya-bean (Glycine max) and cowpea (Vigna unguiculata) root nodules were purified by chromatography on DEAE-cellulose phosphate columns at pH8.0 and pH5.8, to avoid the relatively low pH (5.2) commonly used to purify these proteins. 2. E.p.r. (electron-paramagnetic-resonance) spectra of the fluoride, azide, hydroxide and cyanide complexes of these ferric leghaemoglobins were very similar to the spectra of the corresponding myoglobin derivatives, indicating that the immediate environment of the iron in leghaemoglobin and myoglobin is similar, an imidazole moiety of histidine being the proximal ligand to the haem iron [cf. Appleby, Blumberg, Peisach, Wittenberg & Wittenberg (1976) J. Biol. Chem.251, 6090-6096]. 3. E.p.r. spectra of the acid-metleghaemoglobins showed prominent high-spin features very near g=6 and g=2 and, unlike myoglobin, small low-spin absorptions near g=2.26, 2.72 and 3.14. The width of the g=6 absorption derivative at 10-20K was about 4-4.5mT, similar to the value for acid-methaemoglobin. In contrast, a recently published (Appleby et al., 1976) spectrum of acid-metleghaemoglobin a had less high-spin character and a much broader absorption derivative around g=6. 4. E.p.r. spectra of ferric leghaemoglobin nicotinate and imidazole complexes suggest that the low-spin absorption near g=3.14 can be attributed to a trace of ferric leghaemoglobin nicotinate, and those near g=2.26 and 2.72 are from an endogenous dihistidyl haemichrome. 5. A large e.p.r. signal at g=2 in all samples of crude leghaemoglobin was shown to be from nitrosyl-leghaemoglobin. A soya-bean sample contained 27+/-3% of the latter. A previously unidentified form of soya-bean ferrous leghaemoglobin a was shown to be its nitrosyl derivative. If this is not an artifact, and occurs in the root nodule, the nitrosyl radical may interfere with the function of leghaemoglobin.

SUBMITTER: Maskall CS

PROVIDER: S-EPMC1183675 | biostudies-other | 1977 Nov

REPOSITORIES: biostudies-other

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Project description:The aim of this experiment was to explore transcriptomic changes in the distal gut of Altantic salmon fed five experimental and two control diets. The experimental diets were isonitrogenous, isolipidic and isocaloric. They had similar content of fish meal (~22%) and similar total plant protein content (~45%), but differed in the contents of soya protein concentrate (SPC) and bean protein concentrate (BPC). These two ingredients were used to replace each other (either partially or fully) at the levels of incorporation ranging from 0 to 45%, with ~11% increments. As a result, the experimental diets contained either 45% SPC and 0% BPC (S45), 34% SPC and 11% BPC (S34B11), 22% SPC and 22% BPC (S22B22), 11% SPC and 34% BPC (S11B34) or 0% SPC and 45% BPC (B45). The S45 and B45 diets were single plant protein diets, while the others (S34B11, S22B22 and S11B34) were mixed plant protein diets. The control diets were enriched with fish meal (FM diet) or soybean meal (SBM diet) to provide negative and positive controls for gut inflammation (enteritis), respectively. The study was conducted at EWOS Innovation Research Facility in Dirdal (Norway) Atlantic salmon (Salmo salar L.) of the SalmoBreed strain were supplied as fertilized eggs and hatched on site. Mixed-sex juvenile salmon in groups of ~150 fish were transferred to 26 indoor tanks (0.6 x 0.6 x 0.6 m), with ~60 L of freshwater flowing at a rate of 3.9 L/min and continuous aeration. The temperature of water was regulated at 13°C and all animals were exposed to a constant light regime (24 h light/day). Fish were fed a commercial EWOS Start 1 diet and acclimated to the experimental conditions for 2 weeks, after which (at body mass ~1.5 g) they were subjected to a 56-day feeding trial. Tanks were randomly assigned to the dietary treatments, with 4 replicate tanks per each experimental diet (S45, S34B11, S22B22, S11B34 and B45) and 3 replicate tanks per each control diet (FM and SBM diets). Fish were fed to satiation prior to the feeding trial and during the dietary manipulation using automatic band feeders (Holland Technology, Norway). During the feeding trial, all fish in each tank had their biomass recorded on days 0 (start of experiment), 14, 28, 42 and 56 (end of experiment) for evaluation of growth performance.

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Electron-paramagnetic-resonance studies of leghaemoglobins from soya-bean and cowpea root nodules. Identification of nitrosyl-leghaemoglobin in crude leghaemoglobin preparations.

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