Effects of metal ions on the binding activity of the human leukocyte leukotriene B4 receptor.
The specific binding of leukotriene B4 to its receptor on human leukocyte membranes was enhanced in a dose-dependent manner by metal ions. Mg2+ and Ca2+ were the most potent followed by Mn2+ and Co2+. These divalent cations increased receptor density and did not affect the binding affinity. Addition of the same divalent cations to a partially purified receptor prepared by precipitation with polyethylene glycol produced a greater effect, whereby both binding affinity and receptor density were significantly increased. Zn2+ inhibited activity in both preparations by decreasing the density of receptors. In the membrane preparation, binding activity was decreased by Na+ and increased by K+, while Li+ had no effect. However, in the partially purified receptor preparation, these monovalent cations all increased the binding activity. Our findings show that purification of the leukotriene B4 receptor modifies its response to various monovalent and divalent cations, perhaps by removing certain cellular components involved in receptor regulation.
Ng
C F
CF
Department of Cell Biology, University of Medicine and Dentistry of New Jersey, Stratford 08084, USA. ngca@umdnj.edu
Haeggström
J Z
JZ
Samuelsson
B
B
D002413:Cations, Divalent / Q000494:pharmacology*; D002414:Cations, Monovalent / Q000494:pharmacology; D002462:Cell Membrane / Q000378:metabolism; D006801:Humans; D010714:Phosphatidylethanolamines / Q000737:chemistry; D010718:Phosphatidylserines / Q000737:chemistry; D018102:Receptors, Leukotriene B4 / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*
D002413:Cations, Divalent; D002414:Cations, Monovalent; D010714:Phosphatidylethanolamines; D010718:Phosphatidylserines; D018102:Receptors, Leukotriene B4