1. As an introduction to the relations that obtain in biochemical systems containing several components, some ionic, some dipolar ionic, the solubility of cystine has been investigated in the presence of glycine and neutral salts. 2. Both glycine and sodium chloride increase cystine solubility at all concentrations. The interaction between cystine and ions is, however, diminished with increase ...

1. Hepatic levels of cystathionine synthase and methionine-activating enzyme are significantly lower in rats fed a diet low in methionine and supplemented with cystine than in rats growing at the same rate while maintained on a diet adequate in methionine, with or without cystine supplementation. Cystathionase levels are also decreased, but to a smaller extent. Betaine-homocysteine methyltransf...

The steady-state level of alpha1(I) collagen mRNA is regulated by amino acid availability in human lung fibroblasts. Depletion of amino acids decreases alpha1(I) collagen mRNA levels and repletion of amino acids induces rapid re-expression of alpha1(I) mRNA. In these studies, we examined the requirements for individual amino acids on the regulation of alpha1(I) collagen mRNA. We found that re-e...

The metabolism of certain inorganic forms of sulfur by various autotropic bacteria has been studied extensively in the past. However, investigations dealing with the metabolism of sulfur compounds by the heterotropic bacteria have not been numerous. Such work as has been done (reviewed by Meyers and Porter (1)) indicates that these microbial systems may be quite specific in their requirements f...

Cystinuria is an inherited disorder characterized by impaired reabsorption of cystine in the proximal tubule of the nephron and in gastrointestinal epithelium. The only significant clinical problem is recurrent nephrolithiasis secondary to the poor solubility of cystine in urine. It accounts for no less than 1% of all urinary tract stones. Mutations in two genes, SLC3A1 and SLC7A9, have been id...

By chain extension of polysarcosine with phenylalanine and cystine, nanogels are formed. The facilitate the transport dyes across an artificial mucus coated membrane their release by reductive bond cleavage.

BACKGROUND System x(-) (c) is a heterodimeric transporter, comprised of a light chain, xCT, and heavy chain, 4F2hc, which mediates the sodium-independent exchange of cystine and glutamate at the plasma membrane. In the current study we tested the hypothesis that stable transfection of Madin-Darby canine kidney (MDCK) cells with human xCT and 4F2hc results in the expression of functional system ...

A suppression of the growth rate of rats upon addition of proteins or protein hydrolysates containing little or no tryptophan to 9 per cent casein diets supplemented with cystine has been repeatedly demonstrated (l-5). This effect can be duplicated by adding 0.078 per cent threonine or 0.208 per cent phenylalanine to such diets (6). With 1.5 mg. per cent of niacin or 50 mg. per cent of tryptoph...

BspA is an abundant surface protein from Lactobacillus fermentum BR11, and is required for normal cystine uptake. In previous studies, a mutant strain deficient in BspA (L. fermentum PNG201) was found to be sensitive to oxidative stress. In this study, the biochemical basis for this was explored. It was found that under aerobic batch culture conditions in de Mann-Rogosa-Sharpe medium, both L. f...