Kageyama T, Tanabe K, Koiwai O
Department of Biochemistry, Primate Research Institute, Kyoto University, Japan.
Eur J Biochem. 1991 Nov 15;202(1):205-15. doi: 10.1111/j.1432-1033.1991.tb16364.x.
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 activities 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.
研究了猴胃蛋白酶原表达的发育变化以及多肽之间的结构差异。猴胃蛋白酶原包括五种不同成分，即胃蛋白酶原A-(1-4)和前胃泌素。它们各自的相对水平和比活性在发育过程中发生了显著变化。A型胃蛋白酶原基因的顺序表达尤为值得注意。胃蛋白酶原A-3是新生阶段的主要酶原，占该阶段总胃蛋白酶原的近一半。胃蛋白酶原A-2在4个月大时占主导地位，胃蛋白酶原A-1在幼年和成年阶段占主导地位。胃蛋白酶原A-1、A-2和A-3的酶学性质与胃蛋白酶原A-4和前胃泌素相似，但不完全相同，特别是在激活过程方面。每种胃蛋白酶都能消化各种蛋白质底物，但特异性存在一些差异。分离出了五种胃蛋白酶原的cDNA克隆，并测定了核苷酸序列。每个cDNA分别包含编码15、47和326个氨基酸残基的前导区、原区和胃蛋白酶区，但前胃泌素的cDNA除外，其中原区和胃蛋白酶区分别编码43和329个氨基酸残基。A型胃蛋白酶原表现出高度相似性，蛋白质编码区核苷酸序列中超过96%的碱基相同。Northern分析显示，A型胃蛋白酶原和前胃泌素基因在胎儿期的表达水平较高，并随着发育而增加。
