A simple method for identification of native collagen by reversed-polarity electrophoresis: Short report Short communication

Abstract

The high molecular weight of collagen and the high uncommon amino acid composition (proline and hydroxyproline) make the protein par­ti­cular at structural and physicochemical levels compared to others. Polyacryl­amide gel electrophoresis (PAGE) is a simple and inexpensive method to iden­tify collagen integrity; however, native forms of proteins generally show low quality bands. In this work, we considered the charge of the protein to perform a very simple method to identify the native form of type I collagen, exhibiting an appropriate electrophoretic resolution. First, we determined the collagen charge at different pHs and then modified a previously published method by changing the gel buffer and reversing the polarity of the electrophoresis cham­ber by turning the power cords; now the protein was moved from the anode to the cathode. The result was well-resolved protein bands that maintained their classical structure without degradation after PAGE, which were confirmed by extracting the protein from the native-PAGE and electrophoresing it in a sod­ium dodecyl sulphate-PAGE. This advantage could be useful when the electro­phoresed native collagen is used by Western blotting for recognition with anti­bodies.