CDNA CLONING AND PRIMARY STRUCTURE OF TRYPTASE FROM BOVINE MAST-CELLS, AND EVIDENCE FOR THE EXPRESSION OF BOVINE PANCREATIC TRYPSIN-INHIBITOR MESSENGER-RNA IN THE SAME CELLS

A partial cDNA encoding bovine tryptase, an oligomeric serine proteina se previously isolated from bovine mast cells, was obtained by reverse transcription/polymerase chain reaction of mast cell mRNA, using comb inations of primers designed on the basis of information obtained from partial sequencing of the purified protein. The complete amino acid s equence of bovine tryptase (245 residues) was deduced from a 711-bp nu cleotide sequence and from Edman degradation of the protein. Bovine tr yptase primary structure has an identity of about 75% with tryptases f rom other species and includes all the essential residues of the activ e-site regions; sequence data in the region of the putative substrate binding pocket suggest a rearrangement capable of maintaining the spec ificity of trypsin like proteinases. From the same mast cell mRNA, cDN A encoding bovine trypsin protease inhibitor (BPTI) was obtained and a mplified with specific primers, confirming the synthesis of BPTI in th ese cells. Results are consistent with previous data on the presence o f BPTI and bovine tryptase in the same granules of bovine mast cells a nd with their interaction in vitro.