Binding of serum proteins to polymer gels. II. Binding mechanism to polyoxyphenol-formaldehyde gels

The binding mechanism of proteins to an amorphous polymer gel [formaldehyde-hydroquinone (FA-HQ)], which is a product of addition condensation of hydroquinone with formaldehyde, is examined. Proteins such as serum albumin and gamma-globulin bound to the FA-HQ gel rapidly and irreversibly (without elution by acid, alkali, urea, or detergent solution). The binding of a modified bovine albumin to the FA-HQ gel showed that the blocking of the amino groups in the albumin molecule decreased the amount of protein bound to the gel. Amino acids bound to the FA-HQ gel to a larger extent at alkaline than at neutral pH. These results supported the essential role of the amino groups in binding to the FA-HQ gel. Using the FA-HQ gel-packed glass column or polymer tube, rapid and complete removal of proteins from serum could be carried out, which suggests the usefulness of the gel for the easy pretreatment of biological samples for clinical assays using immobilized enzyme columns.