Separation of functional and non-functional beta subunits of thyrotropin preparations by polyacrylamide gel...

Electrophoretic patterns of intact human and bovine TSH and bovine LH can be clearly distinguished from those of their subunits in 12% polyacrylamide gels, thus providing an easy method of examining subunit recombination. Two distinct components of both bovine and human TSH-beta subunits are observed, of which only one recombines with alpha subunits. Both beta-components cross-react with antisera to TSH and TSH-beta and have, within experimental error, identical amino acid compositions. Thus, the non-recombining component is a non-functional form of TSH-beta which has retained its immunological specificity, and the data explain why the recovery of biological activity during the recombination of TSH subunits is substantially less than with several other glycoprotein hormone preparations.