Azlactone-functional dispersion and reverse phase suspension polymer supports were examined as immobilizing media for Penicillin G Acylase (PGA). Results indicated that the most effective supports were those that also contained primary and/or secondary amide functional groups. A combination of hydrophobic interactions and hydrogen bonding between amide groups on the support and enzyme was proposed to provide important and intimate association between PGA and support prior to covalent coupling. Relative to an oxirane-functional commercial standard, the azlactonc biocatalyst supports featured shorter coupling times and higher catalytic activities. (C) 2005 Elsevier B.V. All rights reserved.