Artificial genes encoding repetitive tripeptide lysyl-aspartyl-phenylalanine (Lys-Asp-Phe) were chemically synthesized and polymerized into a range of size up to 20 repeats of the basic 36-mer unit. The synthetic gene was cloned with expression vector pHK414 and a recombinant plasmid (pAP4-4) which produced a small amount of the artificial protein was isolated. In order to increase size of the artificial protein, repeating sequence of the recombinant plasmid was excised out and concatenated by repeating head-to-tail duplication, while maintaining the reading frame. Clones containing genes coding up to 160 repeats of this tripeptide have been isolated and expressed as cro-LAP-$eta$-Gal fusion proteins. The hybrid proteins accumulated as characteristic insoluble aggregates in E. coli cytoplasm and stably maintained over the culture of 15 generations.