AVS 52nd International Symposium
    Biomaterial Interfaces Wednesday Sessions
       Session BI1-WeM

Paper BI1-WeM11
Enzyme Adsorption as a Model System to Probe Adsorption-Induced Changes in Protein Bioactivity

Wednesday, November 2, 2005, 11:40 am, Room 311

Session: Protein-Surface Interactions
Presenter: K.P. Fears, Clemson University
Authors: K.P. Fears, Clemson University
Y. Sun, Clemson University
R.A. Latour, Clemson University
Correspondent: Click to Email
Although the control of the bioactivity of adsorbed proteins is recognized to be critical for the control of cellular response, little is known about the actual molecular mechanisms involved. Molecular simulation provides great potential to elucidate these mechanisms and to be developed as a tool for surface design to control the orientation, conformation, and bioactivity of adsorbed proteins. The development of accurate molecular simulation methods, however, is critically dependent on the development of experimental methods that can be used to isolate specific molecular events using protein-surface systems that are sufficiently simple to enable them to be represented in molecular simulations. The objective of this research is to experimentally develop model enzyme adsorption systems for this purpose. Homogenous alkanethiol self-assembled monolayers with various end group functionalities are being used in conjunction with surface plasmon resonance spectroscopy to measure the effect of adsorption on protein bioactivity using a set of small enzymes (e.g, lysozyme, trypsin) with known molecular structure, bioactive site, substrate, and native-state bioactivity. An adsorbed trypsin layer on a positively charged surface was measured to be approximately 96% active, only 5% active on a hydrophobic surface, and have no detected activity on a negatively charged surface. It is hypothesized that orientational and conformational effects are primarily responsible for the differences between the charged surfaces and the hydrophobic surface, respectively. Circular dichroism studies are planned to measure the secondary structures of the adsorbed proteins to support this hypothesis.