Figure 4.

Nucleotide and deduced amino acid sequence of a PAP cDNA. Amino acid residues, shown in one letter code, are aligned with the second nucleotide of each codon. A putative secretion signal peptide is underlined. The proteolytic activation site is indicated with “∥.” The double-underlined sequence after the activation site was confirmed by Edman degradation sequencing of the 31-kDa polypeptide isolated from the cuticular extract. The residues of the serine proteinase active site triad are indicated with “★.” An Asp residue predicted to be at the bottom of the substrate binding pocket is labeled with an arrow.