Immobilized Condensed Tannins and Their Interaction with Proteins

Abstract

ABSTRACT Condensed tannins from grapes immobilized on Sepharose 4B were found to have protein binding properties similar to tannins in free solution. Proteins bound to the gel at pH values below their individual isoelectric points and were eluted when the pH was increased. A good correlation was obtained between the isoelectric point and the elution pH for the following enzymes and proteins: alkaline phosphatase, ovalbumin, β‐lactoglobulin, bovine serum albumin, α‐amylase,γ‐globulin, and cytochrome c. Trypsin represented an exception to the rule, α‐Amylase retained enzymatic activity after elution from the gel.