On sequencing peptides formed by LysC digests of guinea pig lung and kidney aminopeptidase P (AmP). we found peptide segments that are highly homologous with three of six conserved blocks characteristic of the protine peptidase family (PPF). It. as we postulate, AmP is a member of the PPF, the order of the conserved blocks (block A is most N-terminal, block F is most C-terminal) provides clues for the design of oligonucleotide primers for cloning a substantial portion of AmP cDNA. Thus, we prepared two forward and two reverse primers: N - representing a novel sequence believed to be closest to the cDNA 5 -end, C- and -C representing block C, and -EF representing parts of blocks E and F (which are virtually fused in AmP). We also used the 3 RACE kit APT primer. RT-PCR was performed using human aortic endothelial cell (HAEC) RNA. NK APT primers produced a 1,000 bp product; N-, -C yielded a 320 bp product; N-, -EF yielded a 630 bp product. We conclude that HAEC contain AmP mRNA. Judging from the MW of the AmP peptide, we have obtained the cDNA that encodes its C-terminal half plus an unlranslated peptide. The N-, -EF segment contains about 200 amino acid residues; the N-, -C segment contains about 100 residues; F is followed by about 100 residues, some probably removed in translation.
|Original language||English (US)|
|State||Published - Dec 1 1996|
ASJC Scopus subject areas
- Molecular Biology