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91.
92.
Iron normal mode dynamics in (nitrosyl)iron(II)tetraphenylporphyrin from X-ray nuclear resonance data
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Rai BK Durbin SM Prohofsky EW Sage JT Wyllie GR Scheidt WR Sturhahn W Alp EE 《Biophysical journal》2002,82(6):2951-2963
The complete iron atom vibrational spectrum has been obtained by refinement of normal mode calculations to nuclear inelastic x-ray absorption data from (nitrosyl)iron(II)tetraphenylporphyrin, FeTPP(NO), a useful model for heme dynamics in myoglobin and other heme proteins. Nuclear resonance vibrational spectroscopy (NRVS) provides a direct measurement of the frequency and iron amplitude for all normal modes involving significant displacement of (57)Fe. The NRVS measurements on isotopically enriched single crystals permit determination of heme in-plane and out-of-plane modes. Excellent agreement between the calculated and experimental values of frequency and iron amplitude for each mode is achieved by a force-field refinement. Significantly, we find that the presence of the phenyl groups and the NO ligand leads to substantial mixing of the porphyrin core modes. This first picture of the entire iron vibrational density of states for a porphyrin compound provides an improved model for the role of iron atom dynamics in the biological functioning of heme proteins. 相似文献
93.
Abdurrahim Kocyigit Ozcan Erel Mehmet S. Gurel Senel Avci Necmeddim Aktepe 《Biological trace element research》1998,65(3):271-281
The aim of this study was to measure the alterations in serum selenium (Se), copper (Cu), zinc (Zn), and iron (Fe) concentrations
and their carrier proteins, ceruloplasmin (Cp), transferrin (Tf) albumin, and related antioxidant enzyme activities, erythrocyte
Cu-Zn Superoxide dismutase (Cu-Zn SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) activities in patients with cutaneous
leishmaniasis (CL). Erythrocyte Cu-Zn SOD activities, serum Cu concentrations, and Cp levels were found to be significantly
higher in the patients group than those of controls. However, GSH-Px and CAT activities and Se, Zn, Fe, and Tf levels were
lower in patients than in the control subjects. There were positive important correlation’s between Cu-Zn SOD and Cp, Cu-Zn
SOD and Cu, Cp and Cu, GSH-Px and Se, and Fe and CAT in the patients group. Our results showed that serum essential trace
elements Se, Zn, Cu, and Fe concentrations and their related enzymes Cu-Zn SOD, GSH-Px, and CAT activities change in CL patients.
The changes may be a part of defense strategies of organism and are induced by the hormonelike substances. 相似文献
94.
D Konukoglu M Ercan M Ayaz S Onen 《Journal of trace elements in medicine and biology》2001,15(2-3):119-122
The objective of the study was to investigate the effect of moderate glomerular dysfunction on oxidative stress. We determined the plasma and erythrocyte malondialdehyde (MDA) levels, as a marker of lipid peroxidation, erythrocyte glutathione (GSH) levels and activities of GSH-Px, GSH Red and SOD as an antioxidant enzymes, and plasma trace element levels containing Fe, Cu and Zn in twenty proteinuric patients (6.8 +/- 5.1 g/day) with moderate glomerular function and in 20 anemic control subjects. We found that the erythrocyte and plasma MDA levels and erythrocyte GSH-Px activities were significantly higher (p < 0.001, p < 0.001, p < 0.001, respectively) and the erythrocyte GSH levels and activities of GSH-Red and SOD activities were significantly lower (p < 0.001, p < 0.001, p < 0.001, respectively) in the patients than in the anemic subjects. Plasma Fe and Zn levels were not to be found significantly different in the patients compared to the anemic subjects. But plasma Cu levels were significantly higher in the patients (p < 0.05) when compared with the levels of anemic subjects. This study was concluded that cellular antioxidant activity decreases in proteinuric patients with moderate glomerular function. This may increase lipid peroxidation reactions by causing oxidative stress in erythrocyte membranes. 相似文献
95.
Conventional methods for histological preparation of degenerated myelin are time-consuming and difficult. The purpose of our study was to shorten the time required for the procedure and to obtain better quality results for light microscopic demonstration of degenerated myelin in the central and peripheral nervous systems by using microwave irradiation. Rat brain and sciatic nerve were used for the study. The middle cerebral artery was occluded and the sciatic nerve was cut to produce myelin degeneration. Marchi's method was used for staining degenerated myelin. Fixation for light microscopy that would take two days using the conventional procedure was completed in 16.5-18.5 min using microwave irradiation. While staining of degenerated myelin requires 10 days for the conventional Marchi method, we decreased it to 7 h for brain tissue and 1 h for sciatic nerve by using the microwave oven. Moreover, a better quality preparation was achieved in the groups stained under microwave irradiation than those prepared by the conventional method. 相似文献
96.
Keskil ZA Sipahi EY Oğuz A Ercan ZS 《Prostaglandins, leukotrienes, and essential fatty acids》1998,58(6):395-397
It is well known that in haemodialysis patients suffering from oligoanuria, extracellular hypervolaemia develops and this hypervolaemia is the main reason for hypertension occurring in some of the patients. The absence of vasorelaxation during hypervolaemia may be secondary to an increased activity of vasoconstrictor systems and/or a decreased formation of vasodilator agents like prostaglandin E2(PGE2) and prostaglandin I2(PGI2). In the present study, arterial PGE2 and leukotriene C4(LTC4)-like activities and the effect of fluid removal on these arachidonic acid metabolites during haemodialysis were measured in normotensive and hypertensive patients. Plasma PGE2 and LTC4-like activities were significantly different between hypertensive and normotensive patients. PGE2/LTC4 ratio did not change in normotensive patients while it was increased in hypertensive patients after haemodialysis. These results indicate that haemodialysis alters the synthesis of arachidonic acid metabolites especially in hypertensive patients. 相似文献
97.
Escherichia coli endotoxin (LPS) when infused through the renal artery of the rabbit isolated perfused kidney prepared as constant pressure mode, caused a decrease in flow rate and kidney weight indicating its primary vasoconstrictor effect. This effect was predominant in kidneys from rabbits pretreated with LPS. Endothelin-1 at a concentration of 10(-10) M and big endothelin-1 at a concentration of 10(-8) M produced equal vasoconstrictor effects in kidney. Addition of endotheHn converting enzyme inhibitor, phosphoramidon, to the perfusion medium at a concentration of 10(-6) M caused a reduction in the effects of both LPS and big ET-1 without altering the vasoconstrictor effect of ETol. However, addition of methylene blue (10(-5) M), a soluble guanylate cyclase inhibitor and N(G)-nitro-L-arginine-methyl ester (10(-6) M) to the perfusion medium caused a potentiation in the vasoconstrictor effect of LPS. Indomethacin at a concentration of 10(-6) M did not alter the effect of LPS. These results were taken as evidence for the participation of endothelin peptides and the L-arginine-nitric oxide pathway in the effect ofLPS in rabbit isolated perfused kidney. 相似文献
98.
N Ozer M Müftüoglu D Ataman A Ercan I H Ogüs 《Journal of biochemical and biophysical methods》1999,39(3):153-159
Xanthine oxidase, a commercially important enzyme with a wide area of application, was extracted from fresh milk, without added preservatives, using toluene and heat. The short purification procedure, with high yield, consisted of extraction, ammonium sulfate fractionation, and DEAE-Sepharose (fast flow) column chromatography. Xanthine oxidase was eluted as a single activity peak from the column using a buffer gradient. The purification fold, specific activity and yield for the purified xanthine oxidase were 328, 10.161 U/mg and 69%, respectively. The enzyme was concentrated by ultrafiltration, although 31% of the activity was lost during concentration, no change in specific activity was observed. Activity and protein gave coincident staining bands on native polyacrylamide gels. The intensity and the number of bands were dependent on the oxidative state(s) of the enzyme; reduction by 2-mercaptoethanol decreased the intensity of the slow-moving bands and increased the intensity of the fastest-moving band. Following sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), two major bands (molecular masses of 152 and 131 kDa) were observed, accounting for > or = 95% of xanthine oxidase. Native- and SDS-PAGE showed that the purified xanthine oxidase becomes a heterodimer due to endogenous proteases. 相似文献
99.
Terbiyik Tuba; Cevik Cem; Toklu-Alicli Benin; Sarihan Ercan 《Journal of plankton research》2007,29(8):721-726
The first record of Ferosagitta galerita in the MediterraneanChaetognatha fauna is reported. The morphological and ecologicalfeatures of this species, which was hitherto only known to livenear Madagascar in the Indian Ocean, are given in detail. Withthis new finding, the number of chaetognath species to be knownin the Mediterranean Sea is increased. 相似文献
100.
Istemihan Tengiz Ertugrul Ercan Fahri Sahin Emin Alioglu Can Duman Guray Saydam Filiz Buyukkececi 《Trials》2005,6(1):1-5