Immobilization of acetyl-CoA:arylamine N-acetyltransferase and the preparation of an enzyme reactor for the synthesis of [formula omitted

Abstract

The enzyme arylamine acetyltransferase (acetyl-CoA:arylamine N-acetyltransferase, EC 2.3.1.5) from pigeon liver is immobilized onto differently derivatized controlled pore glass beads. Different silanes, spacer arms and reactive end-groups were tested, and immobilized enzyme stability tests were performed. From these experiments, the method of choice was selected: immobilization on controlled pore glass beads (24 nm pore size, 75–125 μm particle size) derivatized with γ-aminopropyl and glutaraldehyde as the reactive end group. The kinetic properties of an enzyme reactor were investigated and optimized. The goal was to obtain a rapid high-yield conversion of 0.5–1 μmol acetyl-CoA to N-acetylserotonin, so that the reactor is useful for the 11C-labelling of N-acetylserotonin. Using an enzyme reactor (9.8 × 0.5 cm i.d.) containing 4.6 U active arylamine acetyltransferase immobilized onto 930 mg carrier, a 70% conversion of acetyl-CoA was obtained within 4 min.