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1.
Toshitsugu Yubisui Minoru Tamura Masazumi Takeshita 《Biochemical and biophysical research communications》1981,102(3):860-866
NADH-cytochrome reductase activities in hemolysates of young and old human erythrocytes, and in hemolysates of rabbit reticulocytes and erythrocytes were measured after the separation of the enzyme from the bulk of hemoglobin only by isoelectric focusing. In any cases, a single main peak of the enzyme activity was detected after the electrophoresis in the fraction with pH 6.8 and 8.3 for human and rabbit red cells, respectively. The rabbit enzyme showed more than 30 times higher enzyme activity than that of human erythrocytes under the standard assay conditions. Significant differences of Micahelis constants for cytochrome of the enzyme were found between young and old human erythrocytes, and also between human and rabbit red cells. 相似文献
2.
Ameresh Basu Subhalakshmi Subramanian Leena S. Hiremath Churya SivaRaman 《Biochemical and biophysical research communications》1983,114(1):310-317
Oxidation of the isolated deacetyl acyl-carrier protein subunit of citrate lyase from with Cu2+--phenanthroline complex leads exclusively to intrapeptide disulfide bridge formation indicating that the cysteamine and the cysteine residues are located in close proximity. The S-acetylation of the cysteine residue in deacetyl acyl-carrier protein subunit is catalysed by a citrate lyase ligase preparation in presence of acetate and ATP. Reaction-inactivation of citrate lyase results in deacetylation of the S-acetyl cysteamine residue of the prosthetic group but not of the S-acylated cysteine residue in the acyl-carrier protein. 相似文献
3.
D B Keech A K Mattoo M J Carabott J C Wallace 《Biochemical and biophysical research communications》1976,71(3):712-718
An enzyme system (isocitrate synthase) catalysing the conversion of 2-oxoglutarate to isocitrate has been detected in and partially purified from rat liver. The activity of this enzyme system is dependent on the presence of Mg2+, ATP, and NADPH.The major proportion of the isocitrate synthase was found in the cytosol and its level of activity was related to the nutritional state of the animal, undergoing changes parallel to those observed in the rate of lipogenesis. During purification, the activity of the isocitrate synthase system increased relative to that of isocitrate dehydrogenase (NADP+). 相似文献
4.
The detection of a bound ferredoxin in the photosynthetic lamellae of blue-green algae and other oxygen evolving photosynthetic organisms 总被引:3,自引:0,他引:3
M C Evans S G Reeves A Telfer 《Biochemical and biophysical research communications》1973,51(3):593-596
The presence of an electron transport component with an EPR spectrum similar to that of a ferredoxin has been demonstrated in the blue-green alga , the green alga , and in chloroplasts from sorghum () and beans (). The component is photoreduced at 77°K and is very similar to that previously reported in spinach. It seems likely that this component is a primary electron acceptor in photosynthesis in all of these organisms. 相似文献
5.
Microbodies isolated from sporangia of the aquatic fungus have a mean buoyant density of 1.222 g/cm3 after centrifugation through a linear sucrose gradient, and contain catalase, isocitrate lyase and malate synthase. Microbodies fuse to produce one symphyomicrobody per zoospore at the time of sporogenesis. An increase in density accompanies this process. The symphyomicrobody has a mean buoyant density of 1.292 g/cm3 while the spore's single mitochondrion has a buoyant density of 1.219 g/cm3. Statistical data are also provided for both starting levels and purification of symphyomicrobody and mitochondrial enzyme markers. 相似文献
6.
Robert E. Lynch Barry C. Cole 《Biochemical and biophysical research communications》1980,96(1):98-105
Superoxide dismutase and catalase were not detected in . and several other species of some of which consume oxygen and secrete H2O2. . in suspension formed O2? in the presence of NADH and flavins and extracts of . formed O2? in the presence of either NADH or NADPH. The lack of superoxide dismutase in . could not be attributed to superoxide dismutase in the complex medium in which the organisms were grown because organisms grown in medium in which the superoxide dismutase had been inactivated by heat still contained undetectable amounts. Mycoplasmas appear to be an exception to the rule that organisms which consume O2 synthesize superoxide dismutase. 相似文献
7.
Jiro Sekiya Satoru Tanigawa Tadahiko Kajiwara Akikazu Hatanaka 《Phytochemistry》1984,23(11):2439-2443
Fatty acid hydroperoxide lyase (HPO lyase) was found in green and non-green tobacco cells cultured in vitro. The HPO lyase activity in non-green cells was - of that in green cells. When the cells were transferred from the light to dark conditions or vice versa, cells turned non-green or green according to the light conditions. The HPO lyase activity also changed according to the light conditions, but the changes in HPO lyase activities were not proportional to the changes in chlorophyll contents. These results suggest that at least two types of HPO lyases are present in the green cells. One type of HPO lyase is perhaps common both to the green and non-green cells; another one is chloroplastic. The fatty acid compositions of cells and substrate specificities of HPO lyase differed between green and non-green cells. 相似文献
8.
Kazuyuki Morihara Tatsushi Oka Hiroshige Tsuzuki Yoshiharu Tochino Takashi Kanaya 《Biochemical and biophysical research communications》1980,92(2):396-402
We have established a procedure for converting porcine insulin into human insulin using a serine protease from M497-1 which shows unique specificity against lysine residues on the carboxyl side of the splitting point. Desalanine-(B30)-insulin (DAI) was prepared by digestion of porcine insulin with protease. The coupling between DAI and Thr-OBut was performed by the same enzyme at pH 6.5 with a large excess of the amine component (Thr-OBut) in the presence of high concentrations of organic co-solvents. The highest yield was 85% by 20 h reaction at 37°C. The synthesized [Thr-OBut-B30]-insulin was isolated, then deprotected with trifluoroacetic acid in the presence of anisole to obtain semisynthetic human insulin. 相似文献
9.
S.A. Voelkel K.W. Stuckey C.R. Looney F.M. Enright P.E. Humes R.A. Godke 《Theriogenology》1983,19(3):355-366
Two experiments were conducted to test for the recovery of brucella organisms from uterine flushings and harvested embryos of sero-positive embryo donor females. In Experiment I, 16 sero-positive cows were superovulated with FSH treatments and artificially inseminated at 12, 24 and 36 hours following the onset of estrus with brucella-free semen. At 48 hours after the onset of estrus, one half the potential donor females were administered an intrauterine inoculation of 3.3 to 4.6 × 104 (strain 2308) organisms while the remainder received a control inoculation. In Experiment II, the same 16 cows were similarly administered superovulatory treatments and inseminated following estrus. The uterine inoculation was increased to 1.5 to 2.5 × 108 organisms administered 48 hours following estrus. Samples of recovered flushing medium and homogenized embryo residues were placed into a validated culture system to detect the presence of brucella bacteria. Uterine flushings and embryos recovered from 31 females exhibiting estrus following FSH treatments were free from either field strain or the inoculated (strain 2308) contamination. The flushings obtained from a single female, which did not respond with estrus following FSH treatment but was inoculated at appointment, did contain which was identified as the inoculated strain 2308 and not field strain organisms. These results indicate that brucella contamination of flushing media and harvested embryos will not likely be incurred when collecting embryos from sero-positive donor females. These findings offer further encouragement for the use of embryo transplantation as a method to produce brucella-free offspring from infected cows. 相似文献
10.
The succinate analog itaconic acid was observed to be a competitive inhibitor of the glyoxylate cycle specific enzyme isocitrate lyase (EC 4.1.3.1) in cell-free extracts of Tetrahymena pyriformis. Itaconic acid also inhibited net in vivo glycogen synthesis from glyoxylate cycle-dependent precursors such as acetate but not from glyoxylate cycle-independent precursors such as fructose. The effect of itaconic acid on the incorporation of 14C into glycogen from various 14C-labeled precursors was also consistent with inhibition of isocitrate lyase by this compound. Another analog of succinate which shares a common metabolic fate with itaconic acid, mesaconic acid, had no effect on isocitrate lyase activity in vitro or on 14C-labeled precursor incorporation into glycogen in vivo. In addition, itaconic acid did not affect gluconeogenesis from lactate in isolated perfused rat livers, a system lacking the enzyme isocitrate lyase. These results are taken as evidence that itaconic acid is an inhibitor of glyoxylate cycle-dependent glyconeogenesis Tetrahymena pyriformis via specific competitive inhibition of isocitrate lyase activity. 相似文献
11.
cultures were starved, deciliated and incubated in a reciliation medium in the presence and absence of tunicamycin. This antibiotic was shown to have no effect on the rate of reciliation or the appearance of the organisms even when present in relatively large amounts, although cell division was blocked. A small inhibition of protein synthesis was noted in the presence of tunicamycin, but mannose incorporation was totally abolished. It was concluded that the reciliation of these organisms takes place by a mechanism that does not require the synthesis of glycoprotein. 相似文献
12.
Laura Camardella Guido di Prisco Felice Garofano Anna Maria Guerrini 《Biochemical and biophysical research communications》1975,64(2):773-777
The intracellular localization of NADP-dependent glutamate dehydrogenase has been studied in .Beside cytoplasmic GDH, enzyme activity has been found to be associated with the nuclear fraction in amounts comparable to those reported in nuclei of higher organisms.The yield and distribution of both GDH activities have been analyzed in mutants showing, under particular growth conditions, defective mitochondrial functions. 相似文献
13.
The ICL1 gene encoding isocitrate lyase was cloned from the dimorphic fungus Yarrowia lipolytica by complementation of a mutation (acuA3) in the structural gene of isocitrate lyase of Escherichia coli. The open reading frame of ICL1 is 1668 by long and contains no introns in contrast to currently sequenced genes from other filamentous fungi. The ICL1 gene encodes a deduced protein of 555 amino acids with a molecular weight of 62 kDa, which fits the observed size of the purified monomer of isocitrate lyase from Y. lipolytica. Comparison of the protein sequence with those of known pro- and eukaryotic isocitrate lyases revealed a high degree of homology among these enzymes. The isocitrate lyase of Y. lipolytica is more similar to those from Candida tropicalis and filamentous fungi than to Sacharomyces cerevisiae. This enzyme of Y. lipolytica has the putative glyoxysomal targeting signal S-K-L at the carboxy-terminus. It contains a partial repeat which is typical for eukaryotic isocitrate lyases but which is absent from the E. coli enzyme. Surprisingly, deletion of the ICL1 gene from the genome not only inhibits the utilization of acetate, ethanol, and fatty acids, but also reduces the growth rate on glucose. 相似文献
14.
When acetate-adapted cultures of Chlorella fusca were transferred to nitrogen-free medium containing glucose, isocitrate lyase activity was lost over a period of about 25 h. Using a combination of in vivo isotope labelling and immunoprecipitation with anti-isocitrate lyase IgG it was shown that: 1. The onset of loss of enzyme activity preceeded the complete cessation of enzyme synthesis. 2. Disappearance of isocitrate lyase activity was accompanied by loss of enzyme protein, without accumulation of antigenic protein distinguishable from the normal subunit polypeptide of the enzyme, as judged by SDS gel electrophoresis of immunoprecipitated samples from supernatant cell-free extracts. 3. SDS gel electrophoresis of immunoprecipitated isocitrate lyase revealed the presence of antigenic protein bands of Mr about twice that of the normal subunit polypeptide, but the appearance of these apparent dimer forms did not obviously correlate with enzyme degradation. 4. Isoelectric focusing of immunoprecipitated isocitrate lyase showed that the enzyme became progressively more oxidised during the period of its degradation in vivo. 5. By titrating crude broken cell suspensions with anti-isocitrate lyase antibody, preliminary evidence was obtained for transfer of the enzyme from the soluble fraction to an insoluble form as part of the process of disappearance. 相似文献
15.
The state of the structural integrity of the DNA from mouse myocardial cells has been investigated by utilizing both CsCl density gradient sedimentation and digestion by S1 endonuclease from . The DNA from myocardial cells of young mice sedimented in a narrow peak at the expected density of 1.701 g/cm3, while the DNA from the heart cells of senescent mice became broadly distributed in CsCl gradients, banding even more multimodally in alkaline sucrose gradients. This mode of sedimentation indicates that old mouse DNA becomes partially fragmented. When the native DNA of myocardial cells from 6, 20 and 30 month old mice was treated with single-strand specific S1 endonuclease, it was the DNA from the senescent mice that showed a progressive increase in sensitivity to digestion by the enzyme. The results indicate that the heart DNA of aging mice develops single-stranded gaps in addition to a breakdown into differently sized fragments. 相似文献
16.
F. Malpartida M. Zalacaín A. Jiménez J. Davies 《Biochemical and biophysical research communications》1983,117(1):6-12
The gene encoding the phosphotransferase enzyme that modifies hygromycin B in its producing organism , has been cloned in the vector pIJ41. Two plasmids, pFM4 and pFM6, containing 2.1 and 19.6 kb inserts of DNA, respectively, which express the modifying enzyme, have been isolated. A 3.1 kb PstI restriction fragment from pFM4 was inserted in the vector pIJ350 and the resulting plasmids, pMZ11.1 and pMZ11.2, express the hygromycin B-resistance phenotype. The utility of this dominant marker for cloning experiments is discussed in the text. 相似文献
17.
Grant Shimamoto Richard S. Berk 《Biochimica et Biophysica Acta (BBA)/General Subjects》1980,632(3):399-407
The metabolic fate of acetate, produced during taurine catabolism in Pseudomonas aeruginosa TAU-5, appear to involve the glyoxylate cycle. Organisms grown on taurine have significantly higher levels of malate synthetase and isocitrate lyase than cells grown on nutrient broth, but were comparable to the levels found in acetate-grown organisms. Itaconate, an isocitrate lyase inhibitor, produced a prolonged lag phase and reduced the growth rate of organisms when it was present in the taurine or acetate growth medium. Ethylmethanesulfonate treatment of TAU-5 yielded mutant strains unable to grow on taurine or acetate as sole carbon sources, due to a lack of either malate synthetase or isocitrate lyase. Spontaneous revertants derived from these mutant strains regained the missing enzyme activity and the ability to grow on taurine or acetate. 相似文献
18.
Ronald M. Hamelik Mead M. McCabe 《Biochemical and biophysical research communications》1982,106(3):875-880
An inhibitor of , endodextranase was detected in proteins prepared from batch cultures of , strains representing serotypes through . Affinity chromatography of strain 6715-49 proteins, which apparently were free of endodextranase activity, yielded an active endodextranase and, in a separate peak, the endodextranase inhibitor. The presence of the inhibitor in culture fluids accounts for the absence of endodextranase activity in batch-grown cultures of , known to produce this enzyme. 相似文献
19.
Tetsuo Sawai Laura J. Crane J.O. Lampen 《Biochemical and biophysical research communications》1973,53(2):523-530
The plasma membrane-bound penicillinase of has been purified. Amino acid analysis showed no significant differences in composition between the enzyme and exopenicillinase. Enzyme purified from cultures containing H333PO4 or [3H]-glycerol contained 33P or [3H]-glycerol activity and treatment with 8 M urea, 0.2% sodium dodecyl sulfate at 80° C did not remove the 3H-activity from the enzyme protein. Trypsin readily cleaved the glycerol-containing moiety from the enzyme protein, forming enzyme with molecular weight and heat stability like that of the exoenzyme. Phospholipase D and C also produced enzyme resembling the exo-form. 相似文献