Identification of an ATP-dependent copper transport system in endoplasmic reticulum vesicles isolated from rat liver.
1. This paper identifies and characterizes an ATP-dependent copper transport system in endoplasmic reticulum vesicles isolated from male rat liver. 2. The transporter has a Km of 2.5 +/- 1.2 mumol 1(-1) copper glutathione (CuGSH) and a Vmax of 4.5 +/- 1.3 nmol (mg protein)-1 (5 min)-1 for copper. 3. At a copper concentration of 2 mumol l-1, ATP dependence reaches saturation, with a Km for ATP of 4.7 +/- 2.4 mmol l-1 and a Vmax of 2.8 +/- 0.6 nmol (mg protein)-1 (5 min)-1. 4. The uptake is dependent on ATP hydrolysis, since a low energy analogue of ATP, adenosine 5'-[beta-gamma-methylene] triphosphate tetralithium (AMP.PCP), has no effect on copper uptake. 5. The transporter is a P-type ATPase, since vanadate inhibits uptake with a high degree of specificity (100 mumol l-1 inhibits uptake by 50% at a copper concentration of 2 mumol l-1).
Bingham
M J
MJ
Department of Child Health, University of Dundee, UK.
Burchell
A
A
McArdle
H J
HJ
D000251:Adenosine Triphosphatases / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000494:pharmacology / Q000502:physiology*; D000818:Animals; D003300:Copper / Q000378:metabolism*; D003301:Copper Radioisotopes; D004721:Endoplasmic Reticulum / Q000201:enzymology / Q000378:metabolism*; D004734:Energy Metabolism / Q000502:physiology; D005978:Glutathione / Q000494:pharmacology; D066298:In Vitro Techniques; D007700:Kinetics; D008099:Liver / Q000166:cytology / Q000201:enzymology / Q000378:metabolism*; D008297:Male; D051381:Rats; D017208:Rats, Wistar
D003301:Copper Radioisotopes; C005147:5'-adenylyl (beta,gamma-methylene)diphosphonate; D003300:Copper; D000255:Adenosine Triphosphate; D000251:Adenosine Triphosphatases; D005978:Glutathione; C002630:alpha,beta-methyleneadenosine 5'-triphosphate