Copper transport and cytosolic distribution in normocupric and Cu-loaded fibroblasts

Conference · Thu May 01 04:00:00 EDT 1986 · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)

OSTI ID:5097109

Waldrop, G L; Ettinger, M J

Copper transport kinetics examined in fibroblasts to obtain the kinetic parameters for an extrahepatic cell. Initial velocity (30s) data gave Km (5.7 +/- 0.8 ..mu..M) and Vmax (2.2 +/- 0.2 nmol min/sup -1/ mg/sup -1/) which were comparable to the parameters for hepatocytes. Copper uptake was also detected with His/sub 2/ Cu (Km 10.3 +/- 0.2 ..mu..M) which was proposed as the plasma species that delivers Cu to hepatocytes. Albumin (2 ..mu..M) markedly inhibited Cu-uptake by complexing Cu and zinc competitively inhibited Cu-uptake. Fibroblasts were preincubated with 0.4 mM CuSO/sub 4/ for 48h to determine the effects of increased metallothionein on Cu-transport. Cu-preloading had no significant effect on the initial velocities of Cu-uptake (Km 11.0 +/- 1.3 ..mu..M, Vmax 1.9 +/- 0.1 nmol min/sup -1/ mg/sup -1/). Sephadex G150 profiles of the cytosolic distribution of newly-arrived /sup 64/Cu (15 min) showed three Cu-binding fractions (Mr >300 Kd, approx. = 88Kd and approx. = 10 Kd). A 38 Kd Cu-binding component(s) that was detected with hepatocytes was not detected with fibroblasts. Thus, fibroblasts seem to contain the same Cu-transport system as hepatocytes, and can obtain Cu from His/sub 2/ Cu. At the levels obtained in these experiments, increased metallothionein did not effect Cu-transport. The cytosolic distribution of newly-arrived Cu exhibits tissue-specificity.

• Research Organization: State Univ. of New York, Buffalo
• OSTI ID: 5097109
• Report Number(s): CONF-8606151-
• Conference Information: Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) Journal Volume: 45:6
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ALBUMINS
ANIMAL CELLS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BETA-PLUS DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
CONNECTIVE TISSUE CELLS
COPPER
COPPER 64
COPPER ISOTOPES
DISTRIBUTION
ELECTRON CAPTURE RADIOISOTOPES
ELEMENTS
FIBROBLASTS
HOURS LIVING RADIOISOTOPES
INTERMEDIATE MASS NUCLEI
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
LIVER CELLS
MEMBRANE TRANSPORT
METALLOPROTEINS
METALLOTHIONEIN
METALS
NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
PROTEINS
RADIOISOTOPES
REACTION KINETICS
SOMATIC CELLS
TISSUE DISTRIBUTION
TRACER TECHNIQUES
TRANSITION ELEMENTS