Immunoelectrophoretic characterization of insulin monomers and polymers.
Insulin monomers and polymers were analysed by quantitative immunoelectrophoretic procedures. The Zn-insulin hexamer dissociated reversibly by dialysis against the Zn-free electrophoresis buffer. The Zn-insulin polymers showed precipitin reactions of partial identity. Monomeric salt-free insulin migrated as soluble immune complexes in the antiserum gel. The insulin monomer did not absorb the precipitating antibodies against the Zn-insulin polymers. Thus the polymer structure creates antigenic epitopes absent from the insulin monomer. As insulin is probably released from the beta cells in the relatively stable form of Zn-insulin hexamers, selective monomer assays might underestimate the total content of immunoreactive insulin in the biological fluids. Electroimmunoassay of Zn-insulin immunoreactive antigens in human urine defines a normal reference range of 10-25 ng/ml.
Krøll
J
J
Finsen Laboratory, Copenhagen University Hospital, Rigshospitalet, Denmark.
D006801:Humans; D007122:Immunoelectrophoresis; D007123:Immunoelectrophoresis, Two-Dimensional; D007328:Insulin / Q000737:chemistry / Q000276:immunology*; D011108:Polymers
D007328:Insulin; D011108:Polymers