MOLECULAR-CLONING AND CHARACTERIZATION OF PROLYL ENDOPEPTIDASE FROM HUMAN T-CELLS

The prolyl endopeptidase (PEP) gene of human T cells was amplified by the PCR method and cloned in Escherichia coli. The complete gene consi sted of 2,130 nucleotides corresponding to 710 amino acid residues wit h a calculated molecular mass of 80,750. The nucleotide sequence of th is clone revealed that T cell PEP DNA is 48, 50, and 91% homologous to those of Flavobacterium meningosepticum, Aeromonas hydrophila, and po rcine brain PEP, respectively. This gene was fused to the lacZ sequenc e from E. coli and expressed as a fused protein in E. coli. This fused protein exhibited PEP activity, which was inhibited by Z-Pro-prolinal , a specific inhibitor of PEP. The fused protein was purified on a P-g alactosidase specific affinity column. A polyclonal antibody was raise d against the purified protein. Immunological characterization suggest ed that this protein is different from cytosol-soluble PEP.