Evaluation of surface hydrophobicity of proteins on solid phase using surface plasmon resonance sensor

The structural information of protein molecules on solid phase, such as con formation and orientation , has attracted much attention. In this report, w e try to evaluate structural change of proteins via measurement of the adso rption amount of non-ionic detergent (TritonX-100) to proteins immobilized covalently on the matrix surface by a surface plasmon resonance (SPR) senso r. The adsorption amount of detergent to alpha -glucosidase and apomyoglobi n is dependent on the amount of immobilized proteins and their surface net hydrophobicity. Moreover, it is observed that the adsorption amount of dete rgent to proteins increases in proportion to the denaturation degree of pro teins induced by 6M guanidinium chloride solution. Consequently, it is reve aled that measurement of the adsorption amount of detergent to proteins is applicable to detecting conformational changes of proteins on solid phase.