Comparison of radiochemical purity and tissue binding of labelled insulin prepared by lactoperoxidase and chloramine T iodination.
The radiochemical purity and tissue binding of 125I-insulin labelled by conventional chloramine T method were compared with those of (A14)-monoiodoinsulin prepared by lactoperoxidase iodination. In the first case the labelled insulin was purified on a cellulose column, while (A14)-monoiodoinsulin prepared with the aid of lactoperoxidase was purified on a column of QAE Sephadex A-25. After the digestion of labelled insulin by pronase about 15 percent of diiodoinsulin was found after chloramine T iodination, while a negligible amount (i.e. less than 1 percent) was detected after the use of lactoperoxidase. In addition, no damage of insulin molecules was found after the use of the latter method and the purification on QAE Sephadex A-25 yielded a homogenous preparation of insulin. Specific binding to isolated rat fat cells, rat liver plasma membranes and human erythrocytes was consistently higher in the case of (A14)-monoiodoinsulin compared to the insulin labelled by chloramine T method.
D000273:Adipose Tissue / Q000378:metabolism; D000818:Animals; D002462:Cell Membrane / Q000378:metabolism; D002700:Chloramines; D004912:Erythrocytes / Q000378:metabolism; D006801:Humans; D007328:Insulin / Q000031:analogs & derivatives* / Q000302:isolation & purification / Q000378:metabolism; D007457:Iodine Radioisotopes; D007784:Lactoperoxidase; D008099:Liver / Q000378:metabolism; D011865:Radioisotope Dilution Technique; D051381:Rats; D011972:Receptor, Insulin / Q000378:metabolism*; D014105:Tosyl Compounds
D002700:Chloramines; D007328:Insulin; D007457:Iodine Radioisotopes; D014105:Tosyl Compounds; C016300:chloramine-T; C008147:insulin, iodo-; D007784:Lactoperoxidase; D011972:Receptor, Insulin