Dietary Control of Cysteine Dioxygenase in Rat Liver

Kohashi, Noriyuki; Yamagata, Kenji; Hosokawa, Yu; Kori, Yoshihiko; Fujii, Osamu; Ueda, Iwao

doi:10.1093/oxfordjournals.jbchem.a132104

Cited by 66 publications

(14 citation statements)

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“…In support of this, our results showed that cysteine supplementation significantly decreased the proportion of protein-bound homocysteine and increased the proportion of non-proteinbound homocysteine in the plasma of rats fed 15S (experiment 3). The lack of cysteine supplementationinduced increase in plasma cysteine concentration observed in rats fed 25C and 25S appears to be due to higher activities of cysteine dioxygenase, the rate-limiting enzyme of cysteine metabolism (1), since it has been shown that the activity of this enzyme increases in response to increase in dietary levels of protein and sulfur amino acids such as methionine and cysteine (35,36).…”

Section: Discussionmentioning

confidence: 99%

Hypohomocysteinemic Effect of Cysteine Is Associated with Increased Plasma Cysteine Concentration in Rats Fed Diets Low in Protein and Methionine Levels

Kawakami

Ohuchi

Morita

et al. 2009

J Nutr Sci Vitaminol

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Summary Rats were fed diets with and without 0.5% L -cysteine supplement for 14 d or shorter periods to clarify the mechanism by which dietary cysteine elicits its hypohomocysteinemic effect. Cysteine supplementation significantly decreased plasma homocysteine concentration with an increase in plasma cysteine concentration in rats fed 10% casein diet (10C) or 15% soybean protein diet (15S) but not in rats fed 25% casein diet (25C) or 25% soybean protein diet. Cysteine supplementation also significantly suppressed hyperhomocysteinemia induced by choline-deprived 10C with an increase in plasma cysteine concentration but not that induced by 25C ϩ 0.65% methionine or 25C ϩ 0.4% guanidinoacetic acid. Hepatic S -adenosylmethionine (SAM) and homocysteine concentrations were significantly decreased by cysteine supplementation of 15S. These decreases in plasma homocysteine concentration and hepatic SAM and homocysteine concentrations due to cysteine supplementation disappeared when 15S was fortified with 0.3% methionine. The plasma homocysteine concentration significantly decreased with an increase in plasma cysteine concentration only 1 d after diet change from 15S to cysteine-supplemented 15S, while hepatic cystathionine ␤ -synthase and betaine-homocysteine S -methyltransferase activities were not altered. Unlike cysteine, cysteic acid and 2-mercaptoethylamine did not decrease plasma homocysteine concentration. These results indicate that cysteine markedly decreases plasma homocysteine concentration only when added to diets low in both protein and methionine levels and suggest that increased plasma cysteine concentration and decreased flow of methionine toward homocysteine formation, but not alteration of homocysteine-metabolizing enzyme activities, are associated with the hypohomocysteinemic effect of cysteine. Key Words hypohomocysteinemic effect, cysteine, homocysteine, low protein diet, low methionine diet Homocysteine is an intermediate in the metabolism of methionine (Fig. 1) ( 1 ), but a number of studies have suggested that an elevated plasma homocysteine concentration is an independent risk factor for cardiovascular disease ( 2 -4 ). It is thought that elevated plasma homocysteine concentrations cause arterial damage by several mechanisms, e.g., endothelial cell injury, platelet activation, and increased oxidizability of low-density lipoproteins ( 4 ). In humans, the normal range of plasma homocysteine concentration is 5 to 15 M , and a 5-M increase in the concentration of this amino acid is associated with a 60-80% increased risk of coronary heart disease ( 3 ). The plasma homocysteine concentration is affected by various factors, such as nutritional, physiological, hormonal, pharmacological, lifestyle, disease, and genetic factors ( 2 -4 ). Of these factors, genetic and nutritional factors are thought to have a greater influence on plasma homocysteine concentration. Many studies have been conducted in humans to investigate the effect of dietary treatments on plasma homocysteine concentration. However, studie...

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Section: Discussionmentioning

confidence: 99%

Hypohomocysteinemic Effect of Cysteine Is Associated with Increased Plasma Cysteine Concentration in Rats Fed Diets Low in Protein and Methionine Levels

Kawakami

Ohuchi

Morita

et al. 2009

J Nutr Sci Vitaminol

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“…Taurine production is largely restricted by the availability of cysteine sulfinate, a product of the CDO-mediated metabolic reaction [31]. Kohashi et al [32] first hypothesized that CDO would play an important role in the regulation of intracellular cysteine. It has also been suggested that the inhibition of taurine production is coupled with the enhancement of GSH synthesis in liver [8,15,33].…”

Section: Discussionmentioning

confidence: 99%

Effects of betaine supplementation on hepatic metabolism of sulfur-containing amino acids in mice

Kim

2005

Journal of Hepatology

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“…This suggests that Nacetylcysteine can provide cysteine which can be utilized for glutathione synthesis by the brain. It is possible that the failure of N-acetylcysteine to maintain elevated plasma and brain cysteine levels at 24 h was due to induction of cysteine dioxygenase which catabolizes excess cysteine (17). Another possibility is that N-acetylcysteine is transported into the cell prior to deacetylation.…”

Section: Resultsmentioning

confidence: 99%

Effect of inhibition of γ-glutamyltranspeptidase by AT-125 (Acivicin) on glutathione and cysteine levels in rat brain and plasma

1985

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AT-125 (Acivicin) is an inhibitor of gamma-glutamyltranspeptidase (gamma-GTP) which initiates glutathione catabolism to cysteine. We measured plasma and brain glutathione and cysteine in rats treated with AT-125. Six h after AT-125 treatment, plasma glutathione had increased 6-fold and plasma cysteine had fallen significantly. Brain cysteine fell after 24 h of AT-125 treatment, and brain glutathione had also decreased 18%. AT-125 pretreatment inhibited brain uptake of 35S when it was given as 35S-GSH but had no effect when it was given as 35S-cysteine. These results suggest that plasma glutathione is catabolized by gamma-GTP, and cysteine derived from it is taken up by the brain. N-acetylcysteine was administered to AT-125 treated rats in an attempt to supply cysteine to the brain in the face of gamma-GTP inhibition. N-acetylcysteine supported brain glutathione levels, suggesting that it can serve as a source of cysteine under these conditions.

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Dietary Control of Cysteine Dioxygenase in Rat Liver

Cited by 66 publications

References 0 publications

Hypohomocysteinemic Effect of Cysteine Is Associated with Increased Plasma Cysteine Concentration in Rats Fed Diets Low in Protein and Methionine Levels

Hypohomocysteinemic Effect of Cysteine Is Associated with Increased Plasma Cysteine Concentration in Rats Fed Diets Low in Protein and Methionine Levels

Effects of betaine supplementation on hepatic metabolism of sulfur-containing amino acids in mice

Effect of inhibition of γ-glutamyltranspeptidase by AT-125 (Acivicin) on glutathione and cysteine levels in rat brain and plasma

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