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21.
M Luciak L Pawlicki J Kedziora K Trznadel J B?aszczyk A Buczyński 《Free radical biology & medicine》1991,10(6):397-401
Six chronic uremic patients on regular hemodialysis treatment were given recombinant human erythropoietin (r-huEPO) in a dose of 50 U/kg of body weight intravenously thrice weekly for 14 weeks. Following r-huEPO therapy, unstimulated whole blood superoxide anion (
2) generation did not change significantly, while opsonized zymosan-stimulated whole blood
2 generation increased. At the same time, erythrocyte superoxide dismutase and, in particular, glutathione peroxidase activities were found to be reducing with concomitant lowering of erythrocyte malonydialdehyde (MDA) concentrations and increase in plasma MDA concentrations. 相似文献
22.
Horse liver contains previously unrecognized isozymes of alcohol dehydrogenase. In contrast to the molecular forms identified up to now, under the conditions employed these variants migrate toward the anode on starch gel electrophoresis and were separated from the cathodic isozymes by DEAE-cellulose chromatography. They were then purified on agarose-hexane-AMP. Their physicochemical and compositional characteristics are similar to those x alcohol dehydrogenases from human liver. Like these and similar ones from simian liver, they retain most of their activity in the presence of10
mm 4-methylpyrazole, oxidize short-chain primary alcohols very poorly, and appear to prefer longer chain primary alcohols and -hydroxy fatty acids as substrates. 相似文献
23.
M T Makler 《Biochemical and biophysical research communications》1980,94(3):967-973
Myeloperoxidase-H2O2-indole acetate system at pH 7.4 emitted light in visible region. Luminescent spectrum showed a weak peak at or near 480 nm and prominent peaks at or near 550, 580, and 620 nm with deep troughs near 500 and 600 nm. In some cases, no definite peak emissions near 550 and 580 nm, but a prominent broad emission between 550 and 580 nm, is observed. Such spectral patterns in the region of 510 to 620 nm were quite similar to those report for the luminescence of photo-products formed from the indole analogs (tryptophan and indole) in 50% alcohol irradiated by U.V. (365 nm) at 77°K, assuming red shift (20–25 nm) by solvent effect. Possible formation of indole acetate cation radical (a precursor of excited indole acetate) was discussed. 相似文献
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Dani Permana Kosuke Minamihata Tsuneyuki Tatsuke Jae M. Lee Takahiro Kusakabe Masahiro Goto Noriho Kamiya 《Biotechnology journal》2019,14(6)
The polymerization of proteins can create newly active and large bio‐macromolecular assemblies that exhibit unique functionalities depending on the properties of the building block proteins and the protein units in polymers. Herein, the first enzymatic polymerization of horseradish peroxidase (HRP) is reported. Recombinant HRPs fused with a tyrosine‐tag (Y‐tag) through a flexible linker at the N‐ and/or C‐termini are expressed in silkworm, Bombyx mori. Trametes sp. laccase (TL) is used to activate the tyrosine of Y‐tagged HRPs with molecular O2 to form a tyrosyl‐free radical, which initiates the tyrosine coupling reaction between the HRP units. A covalent dityrosine linkage is also formed through a HRP‐catalyzed self‐crosslinking reaction in the presence of H2O2. The addition of H2O2 in the self‐polymerization of Y‐tagged HRPs results in lower activity of the HRP polymers, whereas TL provides site‐selectivity, mild reaction conditions and maintains the activity of the polymeric products. The cocrosslinking of Y‐tagged HRPs and HRP‐protein G (Y‐HRP‐pG) units catalyzed by TL shows a higher signal in enzyme‐linked immunosorbent assay (ELISA) than the genetically pG‐fused HRP, Y‐HRP‐pG, and its polymers. This new enzymatic polymerization of HRP promises to provide highly active and functionalized polymers for biomedical applications and diagnostics probes. 相似文献
27.
The relationship between the formation of cell wall-bound ferulic acid (FA) and diferulic acid (DFA) and the change in activities of phenylalanine ammonia-lyase (PAL) and cell wall-bound peroxidase (CW-PRX) was studied in rice shoots. The length and the fresh mass of shoots increased during the growth period from day 4 to 6, while coleoptiles ceased elongation growth on day 5. The amounts of FA and DFA isomers as well as cell wall polysaccharides continued to increase during the whole period. The activities of PAL and CW-PRX greatly increased in the same manner during the period. There were close correlations between the PAL activity and ferulate content or between the CW-PRX activity and DFA content. The expression levels of investigated genes for PAL and putative CW-PRX showed good accordance with the activities of these enzymes. These results suggest that increases in PAL and CW-PRX activities are cooperatively involved in the formation of ferulate network in cell walls of rice shoots and that investigated genes may be, at least in part, associated with the enzyme activities. The substantial increase in such network probably causes the maturation of cell walls and thus the cessation of elongation growth of coleoptiles. 相似文献
28.
The roles of veratryl alcohol and nonionic surfactant in the oxidation of phenolic compounds by lignin peroxidase 总被引:1,自引:0,他引:1
Huang X Wang D Liu C Hu M Qu Y Gao P 《Biochemical and biophysical research communications》2003,311(2):491-494
Veratryl alcohol (VA) at higher concentration stimulated the lignin peroxidase (LiP)-catalyzed oxidation of phenolic compounds remarkably. This novel phenomenon was due to its competition with the phenols for the active site of the enzyme and to the high reactivity of the formed cation radical of VA (VA+*) which resulted in an additional oxidation of the phenols. The influence of the nonionic surfactant Tween 80 on the VA-enhanced LiP-catalyzed oxidation of phenols depended on its concentration. At lower concentration it had a small synergetic effect but at higher concentration it decreased the initial rate. Studies of the capillary electrophoretic behavior of LiP in the presence of Tween 80 showed that this effect was caused by the surfactant aggregation on LiP which, at higher surfactant concentrations, might impede the access of VA to its binding site on LiP and, consequently, the VA+* formation. 相似文献
29.
Lin Yan Philip G. Reeves LuAnn K. Johnson 《Journal of trace elements in medicine and biology》2010,24(4):223-229
We assessed the bioavailability of selenium (Se) from a protein isolate and tofu (bean curd) prepared from naturally produced high-Se soybeans. The Se concentrations of the soybeans, the protein isolate and tofu were 5.2 ± 0.2, 11.4 ± 0.1 and 7.4 ± 0.1 mg/kg, respectively. Male weanling Sprague–Dawley rats were depleted of Se by feeding them a 30% Torula yeast-based diet (4.1 μg Se/kg) for 56 days, and then they were replenished with Se for an additional 50 days by feeding them the same diet containing 14, 24 or 30 μg Se/kg from the protein isolate or 13, 23 or 31 μg Se/kg from tofu, respectively. l-Selenomethionine (SeMet) was used as a reference. Selenium bioavailability was determined on the basis of the restoration of Se-dependent enzyme activities and tissue Se concentrations in Se-depleted rats, comparing those responses for the protein isolate and tofu to those for SeMet by using a slope-ratio method. Dietary supplementation with the protein isolate or tofu resulted in linear or log-linear, dose-dependent increases in glutathione peroxidase activities in blood and liver and in thioredoxin reductase activity in liver. Furthermore, supplementation with the protein isolate or tofu resulted in linear or log-linear, dose-dependent increases in the Se concentrations of plasma, liver, muscle and kidneys. These results indicated an overall bioavailability of approximately 101% for Se from the protein isolate and 94% from tofu, relative to SeMet. We conclude that Se from naturally produced high-Se soybeans is highly bioavailable in this model and that high-Se soybeans may be a good dietary source of Se. 相似文献
30.