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401.
Doris Godde 《Archives of microbiology》1982,131(3):197-202
NADH-plastoquinone-oxidoreductase bound to the membrane fraction of Chlamydomonas reinhardii CW-15 has been solubilized with triton X-100. By treatment with high concentrations of MgCl2 and KCl and (NH4)2SO4 fractionation the enzyme could be enriched 8–10-fold. Spectral properties indicated a flavoprotein probably containing Fe–S groups. The enzyme oxidizes NADH and NADPH with various quinones as electron acceptors. Plastoquinone 1 is an effective electron acceptor, whereas ubiquinone 1 is only reduced with low activity. The enzyme is sensitive to rotenone and thenoyltrifluoroacetone, both inhibitors of ubiquinone reduction by mitochondrial dehydrogenases. As the bound enzyme is sensitive to inhibitors of photosynthetic electron flow, the enzyme is assumed to be responsible for light driven hydrogen evolution at the expense of NADH generating substrates.Abbreviations BQ
benzoquinone
- chl
chlorophyll
- DBMIB
dibromothymoquinone
- DNP-INT
dinitro-phenylether of 2-iodo-4-nitrothymol
- DCMU
3-(3,4-dichlorophenyl)-1,1-dimethylurea
- UHDBT
5-n-undecyl-6-hydroxy-4,7-dioxy-benzothiazol
- TTFA
thenoyltri-fluoroacetone 相似文献
402.
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404.
Masako Tani Tohru Fushiki Kazuo Iwai 《Biochimica et Biophysica Acta (BBA)/General Subjects》1983,757(3):274-281
The absorption of [14C]pteroylglutamic acid (PteGlu) bound to the folate-binding protein of bovine milk was investigated in rat gastrointestinal tract in vivo and in situ. When bound [14C]PteGlu was given to rat intragastrically via oral intubation, a considerable amount of PteGlu was released from folate-binding protein under the acidic conditions in stomach, and it recombined with folate-binding protein in jejunum in vivo. Compared with free PteGlu, bound PteGlu was more gradually absorved in small intestine, but finally the total amount of bound PteGlu absorved was almost the same as that of free PteGlu. In all experiments in situ, bound PteGlu was only slightly absorbed in jejunum, where free PteGlu was rapidly absorved under the same conditions. On the other hand, the absorption rates of the two forms of PteGlu were almost similar to each other in ileum. These results suggest that PteGlu bound to folate-binding protein is absorbed by a manner different from that of free PteGlu in rat gastrointestinal tract. 相似文献
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406.
Cáit Coyle Pat Duggan Margery Godinho Dr. Dave McGrath 《International journal of phytoremediation》1999,1(2):189-202
The proposed phytoremediation technique is based on the successful exploitation and optimization of oxidative coupling, mediated by horseradish peroxidase. Susceptibility to degradation of a selection of phenolic compounds, in solution, by horseradish peroxidase appears to be structurally related and was found to be of the order 2,4-dichlorophenol (2,4-DCP) > 4-chlorophenol (4-CP) > 2-chlorophenol (2-CP). Only 1.89% of 2,4-DCP, at an initial concentration of 5 mM, remained unchanged at the end of the experiment. Reaction rates between purified horseradish peroxidase and 2,4-DCP were found to be extremely rapid with 74% of the substrate removed from solution during the first 30 s. Inhibition of the reaction by the heavy metals Cd, Zn, Ni, and Pb at concentrations of 100 mg/l is of concern because these metals are often present in contaminated soils. H2O2 has a dominant role in optimizing peroxidase activity in crude horseradish extracts. Fluctuations in temperature and pH, normally experienced in soils, did not appear to have a detrimental impact on peroxidase activity. However, the functioning of the enzyme is seriously affected at a pH ≤ 3. All reactions in this study were carried out in solution. 相似文献
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Henri Faure Alain Favier Michele Tripier Josiane Arnaud 《Biological trace element research》1990,24(1):25-37
In this paper we report a method for measuring ultrafiltrable zinc in human serum by electrothermal atomic absorption spectrophtometry.
We show also that ultrafiltration permits to determine alpha-2 macroglobulin bound zinc and losely bound zinc if a strong
zinc ligand (EDTA) is added to serum before ultrafiltration. This last fraction, after deduction of ultrafiltrable zinc, represents
roughly all albumin bound zinc. In 20 controls we found that ultrafiltrable zinc amounted 0.311 μmol/L (S.D.=0.117 μmol/L),
alpha-2 macroglobulin bound zinc 3.08 μmol/L (S.D.=0.221 μmol/L), and albumin bound zinc 12.11 μmol/L (S.D.=1.95 μmol/L).
Our method needs only a small volume of serum, it is simple and rapid but also very accurate and reliable. The losely bound
fraction is very dynamic and, representing the physiologically active part of serum zinc, it could be a good marker of zinc
deficiency. 相似文献
409.
《Journal of Plant Interactions》2013,8(1):468-477
A study was conducted to determine how total phenolic (TP), protein precipitable phenolic (PPP), C, and N concentrations, and amount of protein bound (PB) by PPP in leaves of Desmodium paniculatum (panicled tick-clover; PTC) and Lespedeza cuneata (sericea lespedeza; SL) were affected by simulated herbivory and plant ontogeny. All PTC treatments resulted in a decrease (P ≤ 0.05) in TP, PPP, C, and N concentrations and PB between vegetative and seed set stages. All SL treatments resulted in increased (P ≤ 0.05) or stable TP and PPP concentrations from vegetative stage to seed set. The amount of PB was greatest (P ≤ 0.05) in SL plants submitted to 25% defoliation, and flowering and seed set stages had greater (P ≤ 0.05) PB than the vegetative stage. Ontogenesis and defoliation did not (P > 0.05) affect SL N and C concentrations. The protein binding characteristics of PPP from PTC, but not that of SL, appear to be altered in response to stress. Results might correspond with seed dispersal strategies of the two species, with PTC's epizoochory making increased palatability at seed set beneficial. 相似文献
410.