Primary structures of canine pancreatic lipase and phospholipase A2 messenger RNAs.

cDNA clones coding for phospholipase A2 and lipase mRNA have been identified in a full-length cDNA library constructed from canine pancreatic poly (A) + mRNA. Phospholipase A2 mRNA contains 562 nucleotides and codes for a preproenzyme of 146 amino acids (Mr = 16,251) containing a 15 residue signal peptide (MetLysPheLeuValLeuAlaAlaLeuLeuThrValAlaAlaAla), a seven residue activation peptide (GluGlyGlyIleSerProArg), and a 124 residue mature enzyme, phospholipase A2 (79.2% homology with the porcine enzyme). The 5' nontranslated sequence contains a region where eight of nine bases show potential hybridization to the 3' end of 18S ribosomal RNA. Lipase mRNA contains 1,493 nucleotides and codes for a preenzyme with 467 amino acids (Mr = 51,489) which contains a 17 residue signal peptide (MetValSerIleTrpThrIleAlaLeuPheLeuLeuGlyAlaAlaLysAla) and a 450 residue mature enzyme, lipase (75.6% homology with porcine lipase). The 5' noncoding sequences for phospholipase A2 (28 bases) and lipase (34 bases) mRNAs both have an adenosine base three positions preceding the AUG initiation codon but otherwise demonstrate no homology.