Browse
Submit Data
Databases
API
Help

Dataset Information

8 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Cystine exodus from normal leucocytes is stimulated by MgATP.

ABSTRACT: Cystine exodus from partially purified granular fractions of normal leucocytes is stimulated by MgATP. N-Ethylmaleimide, an inhibitor of the lysosomal H+-translocating ATPase, eliminated the stimulated exodus, but had no effect on basal exodus. As the initial content of cystine was increased, the initial velocity of both the basal and ATP-stimulated egress increased. However, as saturation with substrate was approached, the ATP stimulation disappeared leaving only the N-ethylmaleimide-insensitive basal exodus. The increased initial velocity in the presence of ATP may represent improved binding of cystine to the partially saturated inner transporter as a result of conformational or charge optimization brought about by the action of the H+-translocating ATPase.

SUBMITTER: Greene AA

PROVIDER: S-EPMC1148308 | biostudies-other | 1987 Sep

REPOSITORIES: biostudies-other

ACCESS DATA

Json Xml

Similar Datasets

BA-Methionine plus Cystine vs Cystine

Project description:Study of sulfur metabolism in BA 2 biologic replicates

2010-11-25 | E-GEOD-25418 | biostudies-arrayexpress

BA-Methionine plus Cystine vs Cystine

Project description:Study of sulfur metabolism in BA

2010-11-25 | GSE25418 | GEO

The isolation and partial characterization of glycolipids of normal human leucocytes.

Project description:1. The lipids of purified human leucocytes were extracted with chloroform-methanol and the extract was washed with water. Glycolipids, isolated by Florisil chromatography, were subjected to mild alkaline hydrolysis and the alkali-resistant fraction was fractionated on a silicic acid column. 2. Three classes of glycolipid were separated. The less polar, containing 3.6% of the total glycolipid hexose as galactose, was tentatively identified as ceramide monohexoside. The major glycolipid fraction was characterized as ceramide dihexosides. The more polar glycolipids comprised 1.6% of the total glycolipid hexose as galactose and glucose (in the molar ratio 2:1) and were non-acidic. This class was separated as a mixture containing ninhydrin-positive glycolipids. 3. The ceramide dihexosides taken from two leucocyte preparations accounted for 15.2% and 16.4% by weight of the total lipids. 4. The carbohydrate moiety of the ceramide dihexosides contained galactose and glucose in the molar ratio 2:1. Partial acid hydrolysis and paper chromatography indicated that the hexoses are present as disaccharides, lactose being identified as one of them. 5. Palmitic acid (C(16:0)) and nervonic acid (C(24:1)) were the major fatty acids of this glycolipid. Hydroxy fatty acids were not detected.

| S-EPMC1264919 | biostudies-other

Proteins of normal hair and of cystine-deficient hair from mentally retarded siblings.

Project description:1. S-Carboxymethylkerateines extracted from normal hair can be fractionated into high-sulphur and low-sulphur proteins similar to those obtained from sheep's wool. Normal human hair gives a major high-sulphur protein of higher molecular weight and S-carboxymethylcysteine content than any isolated from normal sheep's wool. 2. The proteins from cystine-deficient hair can also be divided into high-sulphur and low-sulphur proteins. There is a lower proportion of high-sulphur protein in cystine-deficient hair than in normal hair. 3. The high-sulphur proteins from cystine-deficient hair have an abnormal amino acid composition and in particular are lower in S-carboxymethylcysteine content than the corresponding proteins from normal hair. New components are present and the content of very high-sulphur proteins of high molecular weight is much decreased. The low-sulphur proteins of cystine-deficient hair are probably also deficient in S-carboxymethylcysteine. 4. The proteins of cystine-deficient hair probably resemble those in the normal hair root, except that disulphide-bridge formation has occurred.

| S-EPMC1176799 | biostudies-other

Characteristics of cystine counter-transport in normal and cystinotic lysosome-rich leucocyte granular fractions.

Project description:Normal leucocyte lysosome-rich granular fractions exhibited counter-transport of cystine, confirming that cystine transport across the lysosomal membrane is carrier-mediated. The trans-activation of cystine transport was temperature-dependent but relatively independent of the external Na+ or K+ concentration in phosphate buffer. Counter-transport, measured as uptake of exogenous [3H]cystine, increased with increasing intralysosomal cystine content up to approx. 3 nmol of half-cystine/unit of hexosaminidase activity. The amount of [3H]cystine entering lysosomes loaded with unlabelled cystine decreased when unlabelled cystine was added to the extralysosomal medium. Lysosomal cystine counter-transport was stereospecific for the L-isomer. Cystathionine, cystamine and cysteamine-cysteine mixed disulphide gave evidence of sharing the lysosomal cystine-transport system, although at lower activity than cystine. Other tested amino acids, including arginine, glutamate and homocystine, were inactive in this system. Nine leucocyte lysosome-rich preparations from eight different cystinotic patients displayed virtually no counter-transport of cystine, conclusively establishing that a carrier-mediated system for cystine transport is dysfunctional in cystinotic lysosomes.

| S-EPMC1152516 | biostudies-other

l-Cystine Diamides as l-Cystine Crystallization Inhibitors for Cystinuria.

Project description:l-Cystine bismorpholide (1a) and l-cystine bis(N'-methylpiperazide) (1b) were seven and twenty-four times more effective than l-cystine dimethyl ester (CDME) in increasing the metastable supersaturation range of l-cystine, respectively, effectively inhibiting l-cystine crystallization. This behavior can be attributed to inhibition of crystal growth at microscopic length scale, as revealed by atomic force microscopy. Both 1a and 1b are more stable than CDME, and 1b was effective in vivo in a knockout mouse model of cystinuria.

| S-EPMC5774851 | biostudies-literature

In vivo noninvasive microscopy of human leucocytes.

Project description:Leucocytes play a key role in our immune system, protecting the body against infections using a wide range of biological mechanisms. Effective imaging and identification of leucocytes within the blood stream in patients is challenging, however, because of their low volume fraction in the blood, the high tissue scattering and the rapid blood flow. Spectrally encoded flow cytometry (SEFC) has recently been demonstrated effective for label-free high-resolution in vivo imaging of blood cells using an optical probe that does not require mechanical scanning. Here, we use SEFC to noninvasively image leucocytes at different imaging depths within small vessels in human volunteers, and identify visual differences in cell brightness and nuclei shapes, that would help distinguish between the two most abundant leucocyte types. The observed differences match the in vitro characteristics of isolated granulocytes and mononuclear cells. The results prove the potential of the system for conducting differential leucocyte count and as an effective research tool for studying the function and distribution of leucocytes in humans.

| S-EPMC5638923 | biostudies-literature

Molecular Basis of MgATP Selectivity of the Mitochondrial SCaMC Carrier.

Project description:The mitochondrial matrix is the supplier of cellular ATP. The short Ca(2+)-binding mitochondrial carrier (SCaMC) is one of the two mitochondrial carriers responsible for transporting ATP across the mitochondrial inner membrane. While the ADP/ATP carrier (AAC) accounts for the bulk ADP/ATP recycling in the matrix, the function of SCaMC is important for mitochondrial activities that depend on adenine nucleotides, such as gluconeogenesis and mitochondrial biogenesis. A key difference between SCaMC and AAC is that SCaMC selectively transports MgATP whereas AAC only transports free nucleotides. Here, we use a combination of nuclear magnetic resonance experiments and functional mutagenesis to investigate the structural basis of the MgATP selectivity in SCaMC. Our data revealed an MgATP binding site inside the transporter cavity, while identifying an aspartic acid residue that plays an important role in the higher selectivity for MgATP over free ATP.

| S-EPMC4526376 | biostudies-literature

Dissociation between phytohaemagglutinin-stimulated generation of inositol phosphates and Ca2+ increase in human mononuclear leucocytes.

Project description:We have tested whether phytohaemagglutinin (PHA)-stimulated generation of inositol phosphates (IP) and increases in intracellular Ca2+ can be dissociated in human mononuclear leucocytes. Lowering the incubation temperature from 37 degrees to 25 degrees C decreased PHA-stimulated IP generation by more than 80%, but only marginally affected PHA-stimulated Ca2+ increases. In the absence of extracellular Ca2+, PHA did not stimulate IP generation or Ca2+ increases, although PHA binding to its acceptor sites was not impaired. Increasing extracellular Ca2+ up to 0.15 mM enhanced PHA-stimulated PHA generation but this increase was attenuated by further increasing extracellular Ca2+ to 2.6 mM. Increasing extracellular Ca2+ to 0.3 mM also enhanced PHA-stimulated Ca2+ increases, and further increasing extracellular Ca2+ did not affect it. Co-treatment with 100 microM-prostaglandin E2 completely abolished PHA-stimulated IP generation, but inhibited Ca2+ increases by only 20-30%. These results could be explained by IP-generation-independent Ca2+ increases or by non-linear coupling of IP generation to Ca2+ increases. Since the PHA concentrations required to increase Ca2+ were greater than those required for IP generation, the latter hypothesis can be excluded. Furthermore, the Ca2+ ionophore ionomycin increased intracellular Ca2+ and weakly stimulated IP generation, but with very similar concentration-response relationships. Our data suggest that PHA-stimulated IP generation and Ca2+ increases in human mononuclear leucocytes mainly occur independently of one another rather than sequentially.

| S-EPMC1132756 | biostudies-other

BA-Sulfate vs Cystine

Project description:Study of sulfur metabolism in BA 2 biologic replicates

2010-11-25 | E-GEOD-25419 | biostudies-arrayexpress