Use of recombinant oestrogen binding protein for the electrochemical detection of oestrogen

We have previously reported the development of an electrochemical method to quantitatively detect vertebrate oestrogens using an oestrogen binding protein (EBP1) present in wild type Saccharomyces cerevisiae and Candida albicans cells. However, the assays were complex and slow with both whole cells and cell lysate. In this work we report the transfer of the EBP1 gene to an industrial yeast, the addition of a his tag sequence to simplify purification of the protein, and the oestrogen binding characteristics of the protein. The recombinant protein (Ebp1p-6h) can now be produced by a non-pathogenic cell, and has shown good stability both when in use and when lyophilised. The detection range covers likely environmental concentrations of free oestrogens and the limit of detection is below the environmental concentration that has significant biological effect. In addition the assay period has been reduced to approximately 2 min. This work reports progress toward the construction of a rapid, portable oestrogen sensor that is not restricted to use to the laboratory.