Due to high surface-to-volume ratio porous gold is an attractive material used for fabrication of new solid supports for catalysts and biomolecules. Therefore, porous gold shows an excellent stability and biocompatibility for use in production of new reactors and biosensors. Two methods for preparation of porous gold were used. In the first method direct dealloying of 10 karat gold with concentrated nitric acid for different periods of time was used, whereas in the second method electrodeposition of gold/silver alloys followed by etching with concentrated nitric acid was used. Surface characteristics of the resulting materials such as pore size, particle size, surface roughness and surface area were determined as a function of dealloying time by the application of atomic force and scanning electron microscopies and adsorption studies. Porous gold prepared by these methods was used as a platform for protein immobilization. Acetylcholine esterase, used as a biomarker, was directly attached to the surface of porous gold. Michaelis constants of free enzyme and enzyme immobilized on different porous gold surfaces have been determined spectrophotometrically by application of Ellman's assay and used to compare activities of free and immobilized enzyme.