Preparation of monoiodotyrosine-13-glucagon.
Glucagon was iodinated with the lactoperoxidase method at pH 10.0 in the presence of propylene glycol using a substitution of 0.3 g-atom I/mol glucagon. Under these conditions the reactivity of the iodine to tyrosine at position 13 is found to be 4-fold that of the tyrosine at position 10. The amount of diiodotyrosine was less than one-twentieth that of the monoiodotyrosine at either tyrosine residue. Relatively pure monoiodo[125I]tyrosine-13-glucagon can be separated from other iodoglucagons by means of DEAE-chromatography. Such a homogeneous preparation with a known position of the iodine makes it possible to study a specific interaction between the monoiodoglucagon and the glucagon antisera or the glucagon receptor.
D000596:Amino Acids / Q000032:analysis; D005934:Glucagon / Q000302:isolation & purification; D007467:Iodoproteins / Q000096:biosynthesis* / Q000302:isolation & purification; D007784:Lactoperoxidase; D008722:Methods; D010446:Peptide Fragments / Q000032:analysis; D010544:Peroxidases; D014357:Trypsin
D000596:Amino Acids; D007467:Iodoproteins; D010446:Peptide Fragments; D005934:Glucagon; D007784:Lactoperoxidase; D010544:Peroxidases; D014357:Trypsin