Effects Of Sulfur Amino Acids Research Articles

Effects of Sulfur Amino Acids on Cardiodynamic Parameters of Isolated Rat Heart

Abstract Sulfur-containing amino acids are integral part of molecular mechanisms which underlie many aspects of cellular function and homeostasis, facilitated by reversible changes in oxidation states of sulfur atoms. Dysregulation of these pathways is associated with diverse pathologies, notably of the cardiovascular system, which are typically characterized by inappropriate plasma levels of sulfur-containing amino acids. The aim of this study was to assess the acute, direct effects of sulfur-containing amino acids and inorganic NaHS, as H2S donor, on cardiodynamic parameters in homocysteine treated rats. Moderate hyperhomocysteinemia did not cause significant decrease in myocardial contractility, but our findings suggest that NaHS and L-methionine cause negative effects on cardiac function in hearts of the rats treated with homocysteine, even in a single administration. Further investigations need to be carried out with purpose of better understanding and highlightening the impact of Hcy and sulphur amino acids on cardiac function.

Acute effects of sulfur amino acids on redox status in dl-homocysteine-treated rats

Aim: Aim of this study was to asses possible differences in effects of various sulfur containing compounds on redox balance of cardiovascular system in physiological state and in the early onset of hyperhomocysteinemia, and in this way to enable a closer look into early changes in heart function induced by Hcy and the possibilities of their modulation by sulfur containing compounds.

Effects of sulfur amino acids, l-methionine, l-cystine and l-cysteine on lipoprotein lipase and hormone-sensitive lipase in differentiated mouse 3T3-L1 adipocytes

Rats subcutaneously implanted with AH109A hepatoma cells show hyperlipidemia with high concentrations of serum triglyceride and nonesterified fatty acid, suppression of lipoprotein lipase (LPL), and elevation of hormone-sensitive lipase (HSL) activities during the growth of the hepatoma. Supplementation of the diet with sulfur amino acids such as L: -methionine (Met) and L: -cystine (Cys) improved hyperlipidemia by restoring LPL and HSL activities. In the present study, we have attempted to examine the effects of sulfur amino acids on the activity and mRNA level of LPL and the activity of HSL using 3T3-L1 cells, which are known to differentiate to adipocytes. The adipocytes were incubated with various concentrations of Met, Cys or L: -cysteine (CysH) in the absence or presence of tumor necrosis factor-alpha (TNF-alpha). LPL activity was suppressed by TNF-alpha. In the absence of TNF-alpha, Met, Cys and CysH did not change the LPL activity. In the presence of TNF-alpha, Met and Cys significantly increased the LPL activity, and Met also enhanced the LPL mRNA level. HSL activity was also suppressed by TNF-alpha. In the absence of TNF-alpha, Met enhanced the HSL activity. In the presence of TNF-alpha, Met, Cys and CysH suppressed the HSL activity. Sulfur amino acids such as Met, Cys and CysH affected the LPL activity, mRNA level, and HSL activity in 3T3-L1 adipocytes. Some of these effects of sulfur amino acids were different between LPL and HSL, between the absence and the presence of TNF-alpha, and between 3T3-L1 adipocytes and the adipose tissue from rats.

Effects of Sulfur Amino Acids on Tyrosyl or Serine/Threonine Phosphorylation and Translocation of Cytosolic Compounds to Cell Membrane in Stimulus-treated Human Neutrophils

We investigated the effects of various sulfur amino acids on the phosphorylation of proteins and the translocation of cytosolic compounds to cell membrane in stimulus-treated human neutrophils using specific monoclonal antibodies. D,L-homocysteine and D,L-homocysteine-thiolactone enhanced fMLP-induced tyrosyl phosphorylation of proteins and the translocation of p47phox, p67phox, and rac to the cell membrane in a concentration-dependent manner. L-cystathionine, NAc-L-cysteine and carboxymethylcysteine suppressed the tyrosyl phophorylation and translocation of cytosolic compounds to the cell membrane. L-cystathionine, L-cysteine and NAc-L-cysteine suppressed PMA-induced serine/threonine phosphorylation and the translocation of cytosolic compounds to the cell membrane. L-cysteine, NAc-L-cysteine and D,L-homocysteine enhanced AA-induced serine/threonine phosphorylation and the translocation of cytosolic compounds to the cell membrane, but L-cystathionine had opposite effects. These results indicated that the effects of sulfur amino acids on tyrosyl or serine/threonine phosphorylation and the translocation of p47phox, p67phox, and rac to the cell membrane in the stimulus-treated human neutrophils were in parallel with those of the stimulus-induced superoxide generation reported in previous paper. L-cysteine, D,L-homocysteine and L-cystathionine weakly inhibited lipid peroxidation, but the other sulfur amino acids tested had no effect.

Excess dietary L-cysteine, but not L-cystine, is lethal for chicks but not for rats or pigs.

A comparative species investigation of the relative pharmacologic effects of sulfur amino acids was conducted using young chicks, rats, and pigs. Ingestion of excess Met, Cys, or Cys-Cys supplemented at 2.5-, 5.0-, 7.5-, or 10 times the dietary requirement in a corn-soybean meal diet depressed chick growth to varying degrees. Strikingly, ingestion of excess Cys at 30 g/kg Cys (7.5-times the dietary requirement) caused a chick mortality rate of 50% after only 5 d of feeding. Growth was restored and chick mortality was reduced by supplementing diets containing 25 g/kg excess Cys with KHCO3 at 10 g/kg. Additionally, mortality was prevented by supplementing the drinking water of chicks receiving 25 g/kg supplemental Cys with H2O2 (0.05% final concentration). After young rats and pigs consumed excess Cys or Cys-Cys up to 40 g/kg for 14 d, weight gain was severely depressed, but we observed no mortality. An excess of dietary Cys-Cys>or=48 g/kg caused some mortality in rats. Pigs exhibited rapid recovery from growth-depressing excesses of Cys or Cys-Cys. These results lend credence to the acute toxic effects associated with the ingestion of excess sulfur amino acids and highlight the potential for excess dietary cyst(e)ine to be more pernicious than Met in certain species.

Different effects of sulfur amino acids on prolidase and prolinase activity in normal and prolidase-deficient human erythrocytes

Background Prolidase and prolinase activity is known to be enhanced significantly in some diseases. Recently, the effect of amino acids on prolidase and prolinase activity in normal and prolidase-deficient human erythrocytes was investigated. It was reported that both enzymes were enhanced by glycine and alanine in the presence of MnCl 2. Methods Erythrocytes were isolated from heparinized blood from normal human and a patient with prolidase deficiency. Effects of various sulfur amino acids on prolidase and prolinase activities against iminodipeptides in the presence of 1 or 0.1 mmol/l MnCl 2 were investigated. Results Prolinase activity against prolylglycine in normal and prolidase-deficient erythrocyte lysates was inhibited by l-methionine, NAc- l-methionine and d, l-methionine in a concentration-dependent manner, but d-methionine enhanced the activity in low concentrations (0–20 mmol/l). d, l-Homocysteine inhibited the activity more strongly than other sulfur amino acids tested in a concentration-dependent manner. On the other hand, prolidase activity against glycylproline was enhanced by l-methionine, d-methionine, d, l-methionine, d, l-homocysteine thiolactone and d, l-ethionine. The rates of enhancement by these sulfur amino acids were in the following order: d, l-ethionine > d, l-methionine, d-methionine, d, l-homocysteine thiolactone > l-methionine (10 mmol/l). Conclusion The prolinase activity in normal and prolidase-deficient erythrocyte lysates was inhibited by l-methionine, d, l-ethionine and d, l-homocysteine. On the other hand, prolidase activity in their erythrocyte lysates was enhanced by d, l-ethionine, d-methionine and l-methionine. These results indicate the effects of these sulfur amino acids on prolidase and prolinase activities were different.

Effect of sulfur amino acids on stimulus-induced superoxide generation and translocation of p47 phox and p67 phox to cell membrane in human neutrophils and the scavenging of free radical

Background Various cystathionine metabolites are in the urine of the patients with cystathioninuria. Among these metabolites, cystathionine ketimine significantly enhanced N-formyl-methionyl-leucyl-phenylalanine (fMLP)-induced superoxide generation in parallel with tyrosyl phosphorylation of 45 kDa protein in human neutrophils. Methods We investigated the effect of various sulfur amino acids on fMLP-, phorbol-12-myristate-13-acetate (PMA)- and arachidonic acid (AA)-induced superoxide generation in human neutrophils. In addition, the effects of these sulfur amino acids on the membrane translocation of cytosolic compounds p47 phox and p67 phox and on the scavenging of superoxide anions were investigated. Results When the cells were preincubated with various sulfur amino acids, fMLP-induced superoxide generation was enhanced by d,l-homocysteine and d,l-homocysteine-thiolactone but was inhibited by other sulfur amino acids in a concentration-dependent manner. The AA-induced superoxide was enhanced by l-cysteine, N-acetyl- l-cysteine and d,l-homocysteine. The strength of enhancing effect was: l-cysteine≫ N-acetyl- l-cysteine> d,l-homocysteine. On the other hand, the superoxide generation was weakly inhibited by l-cystathionine. The superoxide generation induced by PMA was weakly inhibited by l-cysteine, N-acetyl- l-cysteine and l-cystathionine. Homocysteine and d,l-homocysteine-thiolactone had no effect. In addition, d,l-homocysteine also enhanced translocation to the cell membrane of cytosolic compounds p47 phox and p67 phox. Conversely, l-cystathionine and N-acetyl- l-cysteine inhibited the translocation to membrane of p47 phox and p67 phox in a concentration-dependent manner. N-acetyl- l-cysteine and l-cysteine revealed scavenging activity against 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals. The sulfur amino acids tested also indicated radical scavenging activity on superoxide anion generated by phenazine methoxysulfate (PMS)–NADH system. Conclusion d,l-homocysteine and d,l-homocysteine-thiolactone enhanced fMLP-induced superoxide generation by the increment of translocation to membrane of p47 phox and p67 phox. l-cystathionine and N-acetyl- l-cysteine suppressed fMLP- and PMA-induced superoxide generation by the inhibition of translocation to membrane of p47 phox and p67 phox. N-acetyl- l-cysteine also had scavenging activity against DPPH radicals and superoxide anion.

O2F1124) - Effect of sulfur amino acids on forskolin-induced formation of cyclic ΛΜΡ in hippocampal slices.

O2F1124) - Effect of sulfur amino acids on forskolin-induced formation of cyclic ΛΜΡ in hippocampal slices.

Influence of Sulfur Amino Acids on Copper Toxicity in Chicks

These experiments were conducted to investigate the effect of level of sulfur amino acids in the diet on response of chicks to high di etary copper. Adding 500 or 750 ppm copper to a diet deficient or just adequate in sulfur amino acids for chicks significantly reduced growth rate and efficiency of food utilization. Adding 0.4% D,L-methionine to the diet prevented both the reduced growth rate and efficiency of food utilization resulting from 500 ppm added copper. Reduction in food efficiency but not growth caused by 750 ppm copper also was prevented by 0.4% methionine. Hepatic copper levels were significantly elevated in chicks fed copper levels of 500 and 750 ppm but 0.4% added methionine significantly reduced the increase. In a second experiment, adding 0.4% D,L-methionine or 0.332% L-cystine to a diet adequate in sulfur amino acids significantly counteracted the growth depression caused by 500 ppm copper. Significant elevation in copper levels of blood plasma and spleen were completely counteracted and elevation of copper levels in liver and bile were signifi cantly reduced by extra dietary sulfur amino acids. Copper levels in the kidney were not significantly affected by any dietary treatment. Sodium sulfate partially counteracted the copper toxicity. The results demonstrate a protective effect of sulfur amino acids against copper toxicity in chicks. J. Nutr. 109.-91-97, 1979.