Coupling of human beta 2-adrenergic receptors: relationship to redox potential.
The purpose of this study was to examine the quantitative relationship between the redox potential of a redox couplet and the alterations it induces in coupling of receptor occupation with enzyme activation. Normal neutrophil membrane preparations containing beta 2-adrenergic receptors were exposed to equimolar mixtures of the following redox couplets: ferrocyanide-ferricyanide, hemoglobin-methemoglobin, ascorbate-dehydroascorbate, lactate-pyruvate, glutathione ox-red, beta-hydroxybutyrate-acetoacetate, and NAD-NADH. There was a linear relationship between the redox potential of the couplets and the degree of change in coupling (p less than 0.001). The apparent redox potential of the high affinity complex was +0.30 +/- 0.093 V. The effect of lactate to uncouple beta-adrenergic receptors was partially blocked by preexposure to isoproterenol. Thus, high affinity state formation is regulated by redox couplets in a manner dependent on their redox potential.
Davies
A O
AO
Department of Medicine, Baylor College of Medicine, Houston, Texas 77030.
D000138:Acidosis / Q000378:metabolism; D000293:Adolescent; D000328:Adult; D006801:Humans; D007545:Isoproterenol / Q000378:metabolism; D009504:Neutrophils / Q000648:ultrastructure; D010084:Oxidation-Reduction; D011943:Receptors, Adrenergic, beta / Q000378:metabolism* / Q000493:pharmacokinetics
D011943:Receptors, Adrenergic, beta; D007545:Isoproterenol