title: Two similar but nonallelic rat pancreatic trypsinogens. Nucleotide sequences of the cloned cDNAs.
abstract: We have cloned and identified mRNA sequences for two rat pancreatic trypsinogens. Nucleotide sequence analysis of the cloned sequences revealed two mRNAs that encode similar, though noallelic, pretrypsinogens. Trypsinogen I mRNA is 804 nucleotides in length, plus an estimated poly(A) tract of 100 nucleotides, and contains a short (13 nucleotide) 5' noncoding region and a 3' noncoding region of 54 nucleotides. It encodes a preproenzyme of 246 amino acids comprising a hydrophobic prepeptide (signal peptide) of 15 amino acids, an activation peptide characteristic of trypsinogens, and an active form of trypsin, 223 amino acids in length, that has 78% amino acid sequence identity with porcine trypsin. Trypsinogen II mRNA has a nucleotide sequence 88% homologous with that of trypsinogen I mRNA and encodes a protein with 89% amino acid sequence identity with trypsinogen I. The enzymes encoded by trypsinogen I and II mRNAs retain the key amino acid residues that determine the characteristic substrate cleavage preference of trypsins and, therefore, represent the rat counterparts of this digestive enzyme. Trypsinogen I mRNA is a major pancreatic mRNA comprising an estimated 2-5% of the total, whereas trypsinogen II mRNA is present at much lower levels.
mesh_terms: D000483:Alleles; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D004247:DNA; D004274:DNA, Recombinant; D009693:Nucleic Acid Hybridization; D010179:Pancreas / Q000201:enzymology*; D012333:RNA, Messenger / Q000302:isolation & purification; D051381:Rats; D011919:Rats, Inbred Strains; D014362:Trypsinogen / Q000235:genetics*
chemical_list: D004274:DNA, Recombinant; D012333:RNA, Messenger; D014362:Trypsinogen; D004247:DNA