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Immobilized carboxypeptidase Y was employed for enzymatic peptide synthesis. The enzyme was immobilized by glutaraldehyde coupling onto microparticulate amino-silica and was used in packed bed reactors in a recirculating mode. Mercuric derivatives of the enzyme were examined for their efficacy in catalyzing peptide synthesis reactions using amino acid methyl esters as the amine component. The kinetics of the Bz-Arg-Met-NH$\sb2$ synthesis reaction was examined using the free and immobilized enzyme. The stability of the immoblized enzyme was examined as a function of pH, temperature, and reactant concentrations. The model tripeptide Met-Leu-Phe was synthesized using an immobilized carboxypeptidase Y reactor-displacement chromatograph system. The following sequence was used for the addition of each amino acid residue to the growing peptide chain: carboxypeptidase Y catalyzed peptide bond formation between an N-protected peptide methyl ester and an amino acid amide, phenacyl-bromide modified carboxypeptidase Y catalyzed deamidation of the resulting peptide amide to form the peptide acid and chemical esterification using thionyl chloride to form the N-protected peptide methyl ester. High performance displacement chromatography was employed for the purification of the intermediate N-protected peptide amides and the final peptide. Feed volumes of up to 500 ml were separated in a single displacement chromatographic run. Step changes in operating temperature and organic solvent content along with the incorporation of a wash cycle between the introduction of the feed and displacer were employed to overcome problems associated with the formation of micells with the aklyltrimethylammonium displacers. In order to increase the water solubility of the peptides the N-protecting group benzoyl-L-agrinine was employed. This N-protecting group was removed by immobilized trypsin at the end of synthesis to recover the desired tripeptide product. The purity and amino acid composition of the final peptide product were confirmed using HPLC and amino acid analysis respectively. A microprocessor controlled system of pumps and valves was employed for the coupling of the immobilized CPY catalyzed Bz-Arg-Met-NH$\sb2$ synthesis reaction and its subsequent purification using displacement chromatography. This system was designed to perform peptide synthesis, chromatographic purification, and the regeneration of the chromatographic column simultaneously by using two identical chromatographic columns in parallel. Following each chromatographic run the purified excess amino acid amide was returned to the reactor thus enabling the process to be carried out in a continual fashion.