Studies on Glycoprotein Hormones

Abstract

It has been demonstrated that human chorionic Gonadotrophin (HCG) is composed of two sub unit’s alpha and beta 1-4. Evidence that sub- units of glycoprotein hormones like luteinizing hormone (LH)5-7 and thyroid stimulating hormone (TSH)8 are non-identical has been provided. Several studies indicate that alpha chains of glycoprotein hormones have nearly identical amino acid sequence. Differences in carbohydrate content and composition have, however, been reported. The hormone specific Beta-chains showed marked difference in amino acid sequence. The conformation of the native molecule is necessary for full biological and immunological activities., since sub-units per-se do not exhibit more than 1-3% of the biological activity of the parent molecule. Recombination of HCG alpha and HCG beta sub units resulted in the restoration of biological activity of the order of 60% and 100%. In this report, we are presenting data on the physio-chemical, biological and immunological properties of HCG and its alpha and beta sub units. The purified HCG used in the present investigation has been obtained by a method not hitherto employed by other workers who used ion exchange chromatography and gel filtration for the purification of HCG.