125I-labelling = 125I-Labelling.

Erythropoietin, the hormone that regulates erythropoiesis in mammals, was 125I-labelled by using the catalytic properties of lactoperoxidase and the H2O2-generating properties of glucose oxidase. This methodology, both rapid and simple, not only produced hormone preparations with high specific radioactivity but also did not substantially alter the biological integrity of erythropoietin when it was assayed in vivo.