Molecular weight relationships among the subunits of human glycoprotein hormones.

The mol wt of the subunits of hLH, hFSH, hCG and hTSH have been studied by the method of polyacrylamide gel electrophoresis in sodium dodecyl—sulfate, after reduction with mercaptoethanol. The isolated α—subunit of hLH had a mol wt of 21,200 daltons and the isolated α—subunit of hCG had a mol wt of 22,300 daltons. The isolated P—subunit of hLH had a mol wt of 18,000 daltons, and the isolated β—subunit of hCG had a mol wt of 35,100 daltons. When measurements were made on intact hormones after mercaptoethanol reduction, the corresponding subunits were easily identified by comparison with patterns obtained after electrophoresis of the isolated subunits, and the resulting mol wt estimates were comparable. After electrophoresis of reduced hTSH, two bands were evident with mol wt = 21,200 and 16,600. When highly purified hFSH, or a mixture of propionic acid dissociated hFSH subunits were examined, only a single major band could be detected, having a mol wt = 24,200. In all instances, SDS—electrophoresis of inta...