The particulate half-cystine-rich copper protein of newborn liver. Relationship to metallothionein and subcellular localization in non-mitochondrial particles possibly representing heavy lysosomes

Porter, Huntington

doi:10.1016/0006-291x(74)90656-1

Cited by 117 publications

(17 citation statements)

References 16 publications

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“…Furthermore, there has been little progress on the study of the exact location of MT degradation in cells, although it was presumed that degradation occurs mainly in the lysosome. Aggregate forms of the protein appear to be located within lysosomes (Porter et al, 1974), suggesting that Cu-MT is not readily degraded in that organelle. When MT is bound to copper, its degradation in the lysosome may not be taken place effectively due to a conformational change of MT.…”

Section: S-labeled Mt By Lysosomal Extracts In the Presence Of Coppermentioning

confidence: 99%

Effect of metal ions on the stability of metallothionein in the degradation by cellular fractions in vitro

Hahn

Yoo²,

Gahl

2001

Exp Mol Med

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Metallothioneins (MT), small molecular weight metal binding proteins are known to play an important protective role against heavy metal toxicity, either as antioxidants or pre-oxidants. However, the mode of metabolic fate of MTs in various metal complexes is not clearly understood. This study was carried out to better understand the mode of selective turnover rate of various form of MT in complexes with different metals. The degradation of in vitro translated mouse 35 S-cysteine-MT was examined in lysosomal or cytosolic fractions from mouse liver by gel electrophoresis and autoradiography. Overnight incubations of MT showed extensive proteolysis in the lysosomal fraction but not in cytosolic fractions. However, Cu 2+ -MT was found to be stable under the same experimental condition. In contrast, Zn did not interfere with MT degradation. These results suggest that lysosomes are chiefly responsible for MT removal and appears to be selective on the metals involved in the MT complex. In vitro, translated, radiolabeled MT provides a suitable substrate for investigating the characteristics of MT degradation.

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Section: S-labeled Mt By Lysosomal Extracts In the Presence Of Coppermentioning

confidence: 99%

Effect of metal ions on the stability of metallothionein in the degradation by cellular fractions in vitro

Hahn

Yoo²,

Gahl

2001

Exp Mol Med

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“…Although we did not identify the constituents in the pellet containing the Cu, information from other studies indicates that they may contain membrane-bound vesicles that accumulate copper (7,(41)(42)(43)(44)(45). Our data on the relationship between the quantities of Cu in the four fractions and those in the liver indicate that the quantities of Cu in the LMW protein fraction were approaching a plateau, whereas those in the HMW protein fraction were continuing to increase.…”

Section: Discussionmentioning

confidence: 53%

Copper-Binding Proteins in Liver of Bluegills Exposed to Increased Soluble Copper under Field and Laboratory Conditions

Harrison¹,

Lam²

1986

Environmental Health Perspectives

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Livers from bluegills exposed to increased soluble copper (Cu) under field and laboratory conditions were analyzed to determine the concentration and distribution of Cu in metalloproteins of different molecular size. Analyses were performed on bluegills collected from the impoundment of the H. B. Robinson Steam Electric Plant (Florence, SC) near the effluent discharge from the power plant, near the water intake to the cooling system, and from a control pond as well as on bluegills exposed under controlled laboratory conditions. Metalloproteins were separated into low molecular weight (LMW), intermediate molecular weight (IMW), and high molecular weight (HMW) fractions by using high-performance liquid chromatography.In the field-exposed bluegills, Cu concentrations in the LMW, IMW, and HMW fractions were highest in bluegills from the discharge site and lowest in those from the control pond. In the laboratory-exposed bluegills, Cu concentrations in the fractions increased with exposure concentration and time. Concentrations of Cu in the LMW protein fraction and pellet of bluegills exposed to 160 jig Cu/L appeared to plateau with long exposure times, whereas those in the HMW fraction continued to increase. Bluegills maintained in 80 ,ug Cu/L water at pH 5.5 accumulated lower concentrations of Cu in the LMW and pellet fractions and higher amounts in the HMW than in those maintained in 80 jig Cu/L at pH 7.0. Mortality was dependent on exposure concentration and duration and was higher in bluegills maintained in water at pH 5.5 than at pH 7.0.

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“…A lysosomal localization of metallothioneins has also been reported by Porter (1974) in the new-born liver and in insects exposed to mercury by Jeantet et al (1980) and Bouquegneau et al (to be published). A lysosomal localization of metallothioneins has also been reported by Porter (1974) in the new-born liver and in insects exposed to mercury by Jeantet et al (1980) and Bouquegneau et al (to be published).…”

Section: Heavy Metal Storage Inmentioning

confidence: 52%

Toxins, Drugs, and Pollutants in Marine Animals

Bolis¹,

Zadunaisky²,

Gilles³

1984

Proceedings in Life Sciences

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The particulate half-cystine-rich copper protein of newborn liver. Relationship to metallothionein and subcellular localization in non-mitochondrial particles possibly representing heavy lysosomes

Cited by 117 publications

References 16 publications

Effect of metal ions on the stability of metallothionein in the degradation by cellular fractions in vitro

Effect of metal ions on the stability of metallothionein in the degradation by cellular fractions in vitro

Copper-Binding Proteins in Liver of Bluegills Exposed to Increased Soluble Copper under Field and Laboratory Conditions

Toxins, Drugs, and Pollutants in Marine Animals

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