scholarly journals Formation of peroxides in amino acids and proteins exposed to oxygen free radicals

1993 ◽  
Vol 289 (3) ◽  
pp. 743-749 ◽  
Author(s):  
S Gebicki ◽  
J M Gebicki
Keyword(s):  
Amino Acids ◽  
Free Radicals ◽  
Oxygen Free Radicals ◽  
Radiation Energy ◽  
Protonated Form ◽  
Isoleucine Leucine ◽  
Protein Peroxidation ◽  
Dilute Aqueous Solutions ◽  
Kinetics Of

Dilute aqueous solutions of BSA or lysozyme gave positive tests for peroxides after exposure to reactive oxygen species. The reactive species were generated by gamma-irradiation, reduction of H2O2 with Fe2+ ions or thermal decomposition of an azo compound. Peroxides were assayed by an iodometric method. Identification of the new groups as hydroperoxides was confirmed by their ability to oxidize a range of compounds and by the kinetics of their reaction with iodide. The hydroperoxide groups were bound to the proteins and their yields (G values) corresponded to 1.2 -OOH groups per 100 eV of radiation energy absorbed for BSA, and 0.8 for lysozyme. The oxygen free radicals effective in protein peroxidation were the hydroxyl and organic peroxyl, but not superoxide or its protonated form. The efficiency of BSA peroxidation initiated by the hydroxyl radicals was 40%. Protein peroxides decayed spontaneously with a half-life of about 1.5 days at 20 degrees C. Exposure of the common amino acids to hydroxyl free radicals showed that six of them (glutamate, isoleucine, leucine, lysine, proline and valine) were peroxidized with similar efficiency to the proteins, whereas the rest were inert or much less susceptible. These results suggest that some proteins may be peroxidized by a variety of agents in vivo and that their subsequent reactions with protective agents, such as ascorbate or glutathione, may decrease the antioxidant potential of cells and tissues.

Ethane production as a measure of lipid peroxidation after renal ischemia

1986 ◽  
Vol 251 (5) ◽  
pp. F839-F843 ◽  
Author(s):  
M. S. Paller ◽  
R. P. Hebbel
Keyword(s):  
Lipid Peroxidation ◽  
Free Radicals ◽  
Superoxide Radical ◽  
Oxygen Free Radicals ◽  
Tissue Injury ◽  
Renal Ischemia ◽  
Radical Scavenger ◽  
Base Line ◽  
Ethane Production

After renal ischemia, oxygen free radicals are formed and produce tissue injury, in large part, through peroxidation of polyunsaturated fatty acids. We used an in vivo method to monitor lipid peroxidation after renal ischemia, the measurement of ethane in expired gas, to determine the time course of lipid peroxidation and the effect of several agents to limit lipid peroxidation after renal ischemia. In anesthetized rats there was no significant increase in ethane production during 60 min of renal ischemia. During the first 10 min of renal reperfusion, there was a prompt increase in ethane production from 2.9 +/- 1.3 to 6.3 +/- 1.9 pmol/min (P less than 0.05). Ethane production was significantly increased during the first 50 min of reperfusion and then rapidly tapered to base-line levels. Preischemic administration of allopurinol to prevent superoxide radical generation or the superoxide radical scavenger superoxide dismutase prevented the increase in ethane production during postischemic reperfusion. These studies confirm that there is increase lipid peroxidation following renal ischemia that can be prevented by agents which limit the formation or accumulation of oxygen free radicals. This in vivo method for measuring lipid peroxidation could also be employed to study the effects of ischemia on lipid peroxidation in other organs, as well as to monitor lipid peroxidation in other forms of injury.

scholarly journals Pharmacological Effects of Salvianolic Acid B Against Oxidative Damage

2020 ◽  
Vol 11 ◽  
Author(s):  
Zhun Xiao ◽  
Wei Liu ◽  
Yong-ping Mu ◽  
Hua Zhang ◽  
Xiao-ning Wang ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Free Radicals ◽  
Clinical Application ◽  
Oxygen Free Radicals ◽  
Salvianolic Acid B ◽  
Related Factor ◽  
Pharmacological Effects ◽  
Hydrogen Atoms ◽  
Salvianolic Acid

Salvianolic acid B (Sal B) is one of the main active ingredients of Salvia miltiorrhiza, with strong antioxidant effects. Recent findings have shown that Sal B has anti-inflammatory, anti-apoptotic, anti-fibrotic effects and can promote stem cell proliferation and differentiation, and has a beneficial effect on cardiovascular and cerebrovascular diseases, aging, and liver fibrosis. Reactive oxygen species (ROS) include oxygen free radicals and oxygen-containing non-free radicals. ROS can regulate cell proliferation, survival, death and differentiation to regulate inflammation, and immunity, while Sal B can scavenge oxygen free radicals by providing hydrogen atoms and reduce the production of oxygen free radicals and oxygen-containing non-radicals by regulating the expression of antioxidant enzymes. The many pharmacological effects of Sal B may be closely related to its elimination and inhibition of ROS generation, and Nuclear factor E2-related factor 2/Kelch-like ECH-related protein 1 may be the core link in its regulation of the expression of antioxidant enzyme to exert its antioxidant effect. What is confusing and interesting is that Sal B exhibits the opposite mechanisms in tumors. To clarify the specific target of Sal B and the correlation between its regulation of oxidative stress and energy metabolism homeostasis will help to further understand its role in different pathological conditions, and provide a scientific basis for its further clinical application and new drug development. Although Sal B has broad prospects in clinical application due to its extensive pharmacological effects, the low bioavailability is a serious obstacle to further improving its efficacy in vivo and promoting clinical application. Therefore, how to improve the availability of Sal B in vivo requires the joint efforts of many interdisciplinary subjects.

Effect of Hyperbaric Oxygen Treatment on Nitric Oxide and Oxygen Free Radicals in Rat Brain

2000 ◽  
Vol 83 (4) ◽  
pp. 2022-2029 ◽  
Author(s):  
Ikram M. Elayan ◽  
Milton J. Axley ◽  
Paruchuri V. Prasad ◽  
Stephen T. Ahlers ◽  
Charles R. Auker
Keyword(s):  
Nitric Oxide ◽  
Free Radicals ◽  
Rat Brain ◽  
Hyperbaric Oxygen ◽  
High Pressures ◽  
Oxygen Free Radicals ◽  
In Vivo Microdialysis ◽  
Sprague Dawley ◽  
Fourfold Increase

Oxygen (O2) at high pressures acts as a neurotoxic agent leading to convulsions. The mechanism of this neurotoxicity is not known; however, oxygen free radicals and nitric oxide (NO) have been suggested as contributors. This study was designed to follow the formation of oxygen free radicals and NO in the rat brain under hyperbaric oxygen (HBO) conditions using in vivo microdialysis. Male Sprague-Dawley rats were exposed to 100% O2 at a pressure of 3 atm absolute for 2 h. The formation of 2,3-dihydroxybenzoic acid (2,3-DHBA) as a result of perfusing sodium salicylate was followed as an indicator for the formation of hydroxyl radicals. 2,3-DHBA levels in hippocampal and striatal dialysates of animals exposed to HBO conditions were not significantly different from controls. However, rats treated under the same conditions showed a six- and fourfold increase in nitrite/nitrate, break down products of NO decomposition, in hippocampal and striatal dialysates, respectively. This increase was completely blocked by the nitric oxide synthase (NOS) inhibitor l-nitroarginine methyl ester (l-NAME). Using neuronal NOS, we determined the NOS O2 K m to be 158 ± 28 (SD) mmHg, a value which suggests that production of NO by NOS would increase approximately four- to fivefold under hyperbaric O2 conditions, closely matching the measured increase in vivo. The increase in NO levels may be partially responsible for some of the detrimental effects of HBO conditions.

THE STIMULATION OF INSULIN RELEASE BY ESSENTIAL AMINO ACIDS FROM RABBIT PANCREAS IN VITRO

1970 ◽  
Vol 47 (3) ◽  
pp. 347-356 ◽  
Author(s):  
R. D. G. MILNER
Keyword(s):  
Amino Acids ◽  
Insulin Release ◽  
Incubation Medium ◽  
Statistical Significance ◽  
Adenosine Monophosphate ◽  
Essential Amino Acids ◽  
Isoleucine Leucine ◽  
Rabbit Pancreas

SUMMARY Pieces of rabbit pancreas were incubated in vitro in an incubation medium containing no glucose or 1·5 mg. glucose/ml. In each of these conditions the effect on insulin release of each of the essential amino acids at 5 mm concentration was studied. Leucine was the only essential amino acid that stimulated insulin release to a level which reached statistical significance in an incubation medium containing no glucose. In medium containing 1·5 mg. glucose/ml., arginine, isoleucine, leucine and lysine stimulated insulin release and phenylalanine inhibited insulin release. Glucagon, theophylline or dibutyryl cyclic adenosine monophosphate stimulated insulin release significantly in the presence of leucine but not in the presence of arginine. Arginine stimulated insulin release in the presence of leucine. The results of these experiments characterize further the difference in the mechanism of action of leucine and arginine on the pancreatic β-cell and indicate possible explanations for results obtained in other species in vivo.

Effects of oxygen-free radicals on proliferation kinetics of cultured rabbit articular chondrocytes

1989 ◽  
Vol 141 (2) ◽  
pp. 262-266 ◽  
Author(s):  
Fran�Oise Vincent ◽  
Herv� Brun ◽  
Elisabeth Clain ◽  
Xavier Ronot ◽  
Monique Adolphe
Keyword(s):  
Free Radicals ◽  
Oxygen Free Radicals ◽  
Articular Chondrocytes ◽  
Proliferation Kinetics ◽  
Kinetics Of ◽  
Rabbit Articular Chondrocytes

scholarly journals A double-isotope method for the measurement of ketone-body turnover in the rat. Effect of l-alanine

1984 ◽  
Vol 219 (1) ◽  
pp. 15-24 ◽  
Author(s):  
W D Reed ◽  
P J Baab ◽  
R L Hawkins ◽  
P T Ozand
Keyword(s):  
Amino Acids ◽  
Ketone Body ◽  
Ketone Bodies ◽  
Isotope Method ◽  
Significant Change ◽  
Kinetics Of ◽  
Double Isotope

The synthesis of 4-3H-labelled ketone bodies, and their use along with 14C-labelled ketone-body precursors, is employed using an ‘in vivo’ rat infusion model to measure ketone-body turnover. The use of two isotopes is necessary to measure ketone-body turnover when ketogenesis may occur from more than one precursor such as glucose and fatty or amino acids. Requirements of isotopic equivalence in terms of metabolic similarity, valid stoichiometry and the lack of differences in the kinetics of relevant enzymes is demonstrated for the 4-3H- and 14C-labelled ketone bodies. The hypoketonaemic effect of L-alanine is shown by two distinct phases after the administration of L-alanine. During the first 12 min after alanine administration ther was a 50% decrease in acetoacetate and a 30% decrease in 3-hydroxybutyrate production, with no significant change in the utilization of either compound. The hypoketonaemic action of alanine during the following 16 min was primarily associated with an uptake of 3-hydroxybutyrate that was somewhat greater than the increase in its production. There were essentially equivalent decreases in production and utilization of acetoacetate, resulting in no significant net change in the level of this ketone body in the blood.

scholarly journals Digestion rate of dietary starch affects systemic circulation of amino acids in weaned pigs

2010 ◽  
Vol 103 (10) ◽  
pp. 1404-1412 ◽  
Author(s):  
Fugui Yin ◽  
Zhenzhen Zhang ◽  
Ju Huang ◽  
Yulong Yin
Keyword(s):  
Amino Acids ◽  
Small Intestine ◽  
Systemic Circulation ◽  
Serum Concentrations ◽  
Weaned Pigs ◽  
Isoleucine Leucine ◽  
Peak Point ◽  
Dietary Starch

The present study was conducted to evaluate the in vitro and in vivo digestibility of dietary starch and its digestive behaviour on the systemic circulating amino acids (AA) in weaned pigs. Eighteen weanling pigs surgically fitted with a catheter in the jugular vein were randomly assigned to three dietary treatment groups. Sticky rice starch (SRS) was hydrolysed more quickly in vitro (P < 0·05) than maize starch (MS) and resistant starch (RS), and was almost completely hydrolysed within 4 h. The in vivo digestibility of dietary starch in different segments of the small intestine was significantly different. SRS was digested (81·9 %; P < 0·05) in the anterior jejunum, but not more than half of the MS and RS was digested in the same segment of the small intestine. The digestibilities of isoleucine, leucine, methionine, phenylalanine, threonine, tryptophan, valine, alanine, aspartate and serine in the SRS group were higher than in the MS group (P < 0·05), and all nutritionally indispensable and dispensable AA in the SRS group were higher when compared with those in the RS group (P < 0·05). The serum concentrations of nutritionally indispensable AA, proline and serine in the three groups were increased to a peak point within 1·5 h postprandially then decreased gradually; however, the time that serum concentrations of alanine, aspartate, glutamate and glycine in each group increased to a peak point was different. The concentrations of nutritionally indispensable AA, including arginine, cystine, histidine, isoleucine, leucine, methionine, phenylalanine, threonine, tryptophan, tyrosine and valine at 09.30 hours and arginine, cystine, histidine, isoleucine, methionine, phenylalanine, threonine, tryptophan, tyrosine and valine at 13.30 hours in the SRS group were higher than in the MS group (P < 0·05); all nutritionally indispensable AA in the SRS group were higher than in the RS group at 09.30 and 13.30 hours (P < 0·05), respectively. We conclude that dietary starches digested rapidly in vitro have higher digestibility in the anterior small intestine of pigs. Diets containing rapidly digestible starch ameliorate the digestive and absorptive function and regulate AA metabolism to beneficially increase the entry of dietary AA into the systemic circulation in pigs.

Effect of ethanol in vivo on enzymes which detoxify oxygen free radicals

1989 ◽  
Vol 7 (2) ◽  
pp. 117-123 ◽  
Author(s):  
Nicholas J. Schisler ◽  
Shiva M. Singh
Keyword(s):  
Free Radicals ◽  
Oxygen Free Radicals
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