Insulin-receptor interactions. Possible involvement of metals.
Addition of Zn2+ or Cu2+ ions to plasma membrane preparations or to purified insulin receptors from rat liver resulted in an increase of specific insulin binding; no effect was observed with the addition of Fe3+, Ca2+ or Na+. Dialysis of membrane preparations, or of purified receptors, against chelating agents such as zincon (2-carboxy-2'-hydroxy-5'-sulfoformazyl-benzene) or 1,10-phenantroline resulted in a decrease in specific binding of insulin. With the readdition of Zn2+ or Cu2+ to the medium an increase in specific binding was observed, and values much higher than those of the original preparations were obtained; the addition of Ca2+, Fe3+ or Na+ to dialyzed preparations did not cause any effect on the specific binding. Dialysis of purified receptors against chelating agents resulted in a decrease in the content of Zn2+ and Cu2+. Zincon has been found to be a competitive inhibitor of insulin interfering with the specific binding to the receptor, and noncompetitive with the nonspecific binding. These results suggest the possible involvement of a metal ion present in the receptor in the formation of the insulin-receptor complex.
Monreal
J I
JI
Departamento de Bioquímica, Universidad de Navarra, Pamplona, Spain.
Viader
C
C
Pérez-Barquero
C
C
López-Moratalla
N
N
de Pablo
P
P
Santiago
E
E
D000818:Animals; D001391:Azo Compounds / Q000494:pharmacology; D002614:Chelating Agents / Q000494:pharmacology; D003956:Dialysis; D005562:Formazans; D066298:In Vitro Techniques; D007328:Insulin / Q000378:metabolism*; D007700:Kinetics; D008670:Metals / Q000032:analysis / Q000502:physiology*; D051381:Rats; D011972:Receptor, Insulin / Q000032:analysis / Q000378:metabolism*
D001391:Azo Compounds; D002614:Chelating Agents; D005562:Formazans; D007328:Insulin; D008670:Metals; C009809:2-carboxy-2'-hydroxy-5'-sulfoformazylbenzene; D011972:Receptor, Insulin