CLONING AND SEQUENCE-ANALYSIS OF THE GENE ENCODING HUMAN LYMPHOCYTE PROLYL ENDOPEPTIDASE

The human cDNA encoding prolyl endopeptidase, a cytoplasmic endoprotea se which hydrolyses the peptide bond at the C-terminal side of proline , was sequenced. After the isolation of the 3' terminal fragment of th e pep cDNA sequence from a human lymphocyte cDNA library, an approach based on the polymerase chain reaction (PCR) was undertaken to obtain the complete pep cDNA. Overlapping DNA fragments were generated by PCR from cDNA synthesized from human lymphocyte mRNA. The DNA fragments w ere subcloned and sequenced. The complete cDNA is 2562 nucleotides (nt ) in length and contains an open reading frame coding for a protein of 710 amino acids (aa). Comparison of the primary PEP sequences from hu man lymphocyte and pig brain shows 97% identity. The aa sequence analy sis shows homology with bacterial PEPs and with protease II from Esche richia coli. Asp(641) probably participates in the active site of PEP.