2-Iodoestradiol

2-Iodoestradiol is a potent human sex hormone binding globulin (SHBG) ligand with a remarkably high affinity for SHBG. 2-Iodoestradiol exhibits competition for the same binding site as dihydrotestosterone in binding to human SHBG. The binding affinity constant of 2-Iodoestradiol at physiological pH and 37 degrees Celsius is 2.4 x 10(9) M-1, exceeding that for SHBG. 2-Iodoestradiol has been shown to bind to serum albumin, but with lower affinity. The radioisotope 125I-derivative of 2-Iodoestradiol has been used to study the binding properties of human SHBG, demonstrating its potential application in biological research.