title: Identification and expression of the cDNA-encoding human mesotrypsin(ogen), an isoform of trypsin with inhibitor resistance.
abstract: The cDNA encoding a novel isoform of human trypsinogen was identified. The isoelectric points of the proenzyme and active forms calculated from the deduced amino acid sequence are consistent with those of mesotrypsin(ogen), known to be an inhibitor-resistant trypsin isoform. The cDNA attached with a bacterial signal peptide sequence was expressed in Escherichia coli. The recombinant proenzyme purified from periplasm showed enterokinase-dependent activation similar to a major isoform of human trypsinogen. The enzyme was far less inhibited by trypsin inhibitors such as soybean trypsin inhibitor, aprotinin, or pancreatic secretory trypsin inhibitor than the control trypsin. A gel filtration assay showed that the enzyme and aprotinin did not form a stable complex. It is noteworthy that the amino acid at position 198, which is in close vicinity to the active Ser, is Arg while those of other major trypsins are all Gly. It is concluded that the cloned cDNA encodes human mesotrypsinogen, a unique isoform of trypsinogen with inhibitor resistance.
authors.affiliation: Research Institute for Food Science, Kyoto University, Uji, Kyoto 611, Japan.
authors.forename: C N
authors.initials: CN
authors.lastname: Nyaruhucha
authors.forename: M
authors.initials: M
authors.lastname: Kito
authors.forename: S I
authors.initials: SI
authors.lastname: Fukuoka
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary; D004351:Drug Resistance; D004792:Enzyme Precursors / Q000096:biosynthesis; D004926:Escherichia coli; D006801:Humans; D007527:Isoenzymes / Q000096:biosynthesis* / Q000737:chemistry / Q000378:metabolism; D007700:Kinetics; D008969:Molecular Sequence Data; D010179:Pancreas / Q000201:enzymology; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D014357:Trypsin / Q000096:biosynthesis* / Q000737:chemistry / Q000378:metabolism; D014361:Trypsin Inhibitors / Q000494:pharmacology*; D014362:Trypsinogen / Q000096:biosynthesis* / Q000378:metabolism
chemical_list: D018076:DNA, Complementary; D004792:Enzyme Precursors; D007527:Isoenzymes; D011994:Recombinant Proteins; D014361:Trypsin Inhibitors; D014362:Trypsinogen; C040749:PRSS3 protein, human; D014357:Trypsin