Products of estradiol/peroxidase interaction; their structural features and biopolymeric character

Loss of tritium from [2,4,6 alpha, 7 alpha-3H]estradiol and from [2-3H]estradiol during their conversion into polyestradiol (PEL) by horseradish peroxidase/H2O2 and the NMR spectrum of PEL permethyl ether suggest that PEL is composed of two or more different subunits, each formed by the joining of four molecules of estradiol with the loss of five hydrogen atoms from positions 2 and 4 and of three phenolic hydrogens leading to the formation of one C-C bond and three C-O bonds. At very low concentrations of estradiol the main reaction products were monomers; this is attributed to the initial formation of transient tetraestradiols which combine with water at high dilution and with themselves at low dilution. Association of the monomeric products to oligomers occurred on a Sephadex G-50 column and was readily reversed in phosphate buffer. In aqueous solution PEL underwent non-covalent changes induced by heat, time and electrolytes, and affecting its solubility, u.v. absorbance, extraction by organic solvents and ability to bind estradiol.