Structure‐function studies of recombinant murine tripeptidyl‐peptidase II: the extra domain which is subject to alternative splicing is involved in complex formation

Tripeptidyl-peptidase II (TPP II) is an exopeptidase with a remarkably high native Mr (> 10(6)). Recently, an alternatively spliced, murine cDNA variant was identified which contains an additional 39 bp, encoding 13 amino acids in the C-terminal end of the protein. The two enzyme variants were expressed in human kidney 293 cells. Both types of subunit were found to form the active oligomers. In addition, subunits containing the extra 13 amino acids formed an even larger complex eluting in the void volume of a Sepharose CL-4B column. Thus, it appears that this sequence is important for aggregation of subunits.