Gonadotropin (LH, FSH, HCG) and thyroid stimulating hormone (TSH) are composed of α and β peptide chains through non-covalent bonds, and contain glycosyl groups, which are covalently bound to a single asparagine residue, serine residue or threonine residue on the peptide chain. These two peptide chains can be separated and recombined. The α peptide chains of LH, FSH, HCG and TSH have the same structure, while the β peptide chains have their own characteristics, which determines the functional specificity of the above hormones.