Application of Circular Dichroism to the Study of Enzyme Polymer Conjugates

Abstract

A very large number of publications have appeared recently on the preparation and characterization of immobilized enzymes (1). Only a few of these, however, have been concerned with understanding the physical nature of these systems through the use of spectroscopic techniques (2–6). One important aspect of any immobilized enzyme is its conformation, a precise knowledge of which could give insight into its specific activity, thermal stability and solvent stability, etc. A physical technique that detects very subtle changes in the conformation of a macromolecule, such as an enzyme, is circular dichroism (CD) (7). This communication presents our preliminary findings of a CD examination of a water soluble ribonuclease A (RNase A) dextran conjugate. Such water soluble systems, some of which have enhanced thermal stability (8), are being used increasingly in ultrafiltration cells or hollow fibers. Further, the results obtained from studies of water soluble systems can aid in explaining the behavior of the corresponding water insoluble enzyme conjugates.