Modular systems for protein coupling have been applied for anchoring enzyme molecules on liposome surfaces. Two cytoplasmic model enzymes, alpha-amylase from Escherichia coli (EC. 3.2. 1. 1) and guanylate kinase from Saccharomyces cerevisiae (EC. 2.7.4.8), were directly coupled by a histidine-tag or indirectly via strep-tag and streptavidin or streptactin linker to a liposome membrane. Though the catalytic properties of the enzymes are generally maintained, stability and specific activity of the enzymes are modified after coupling and are especially influenced by the lipid used for the liposome assembly. (C) 2003 Elsevier Inc.