
Development‐dependent expression of isozymogens of monkey pepsinogens and structural differences between them
Author(s) -
KAGEYAMA Takashi,
TANABE Kazushi,
KOIWAI Osamu
Publication year - 1991
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1991.tb16364.x
Subject(s) - pepsin , complementary dna , biology , amino acid , gene , microbiology and biotechnology , gene expression , biochemistry , enzyme
The developmental changes in the expression of monkey pepsinogens and structural differences between the polypeptides were investigated. Monkey pepsinogens included five different components, namely, pepsinogens A‐1–4 and progastricsin. Their respective relative levels and specific activites changed significantly during development. The sequential expression of genes for type‐A pepsinogens was particularly noteworthy. Pepsinogen A‐3 was the major zymogen at the newborn stage, accounting for nearly half of the total pepsinogens at this stage. Pepsinogen A‐2 became predominant at the 4‐month stage, and pepsinogen A‐1 predominated at the juvenile and adult stages. Enzymatic properties of pepsinogens A‐1, A‐2 and A‐3 were similar but not identical to those of pepsinogen A‐4 and progastricsin, in particular with respect to the activation processes. Each pepsin digested various protein substrates but some differences in specificity were evident. cDNA clones for five pepsinogens were isolated, and the nucleotide sequences were determined. Each cDNA contained leader, pro, and pepsin regions that encoded 15, 47, and 326 amino acid residues, respectively, with the exception of the cDNA for progastricsin in which the pro and pepsin regions encoded 43 and 329 amino acid residues, respectively. Type‐A pepsinogens exhibited a high degree of similarity, with over 96% of bases in the nucleotide sequences of the protein‐coding regions being identical. Northern analysis revealed that the level of expression of genes for type‐A pepsinogens and for progastricsin was significant at the fetal stage and increased with development.