MacDonald R J, Swift G H, Quinto C, Swain W, Pictet R L, Nikovits W, Rutter W J
Biochemistry. 1982 Mar 16;21(6):1453-63. doi: 10.1021/bi00535a053.
The mRNA sequences for two rat pancreatic elastolytic enzymes have been cloned by recombinant DNA technology and their nucleotide sequences determined. Rat elastase I mRNA is 1113 nucleotides in length, plus a poly(A) tail, and encodes a preproelastase of 266 amino acids. The amino acid sequence of the predicted active form of rat elastase I is 84% homologous to porcine elastase 1. Key amino acid residues involved in determining substrate specificity of porcine elastase 1 are retained in the rat enzyme. The activation peptide of the zymogen does not appear related to that of other mammalian pancreatic serine proteases. The mRNA for elastase I is localized in the rough endoplasmic reticulum of acinar cells, as expected for the site of synthesis of an exocrine secretory enzyme. Rat elastase II mRNA is 910 nucleotides in length, plus a poly(A) tail, and encodes a preproenzyme of 271 amino acids. The amino acid sequence is more closely related to porcine elastase 1 (58% sequence identity) than to the other pancreatic serine proteases (33-39% sequence identity). Predictions of substrate preference based upon key amino acid residues that define the substrate binding cleft are consistent with the broad specificity observed for mammalian pancreatic elastase 2. The activation peptide is similar to that of the chymotrypsinogens and retains an N-terminal cysteine available to form a disulfide link to an internal conserved cysteine residue.
通过重组DNA技术克隆了两种大鼠胰腺弹性蛋白酶的mRNA序列，并测定了它们的核苷酸序列。大鼠弹性蛋白酶I的mRNA长度为1113个核苷酸，加上一个聚腺苷酸尾，编码一个含266个氨基酸的前弹性蛋白酶原。预测的大鼠弹性蛋白酶I活性形式的氨基酸序列与猪弹性蛋白酶1有84%的同源性。猪弹性蛋白酶1中决定底物特异性的关键氨基酸残基在大鼠酶中得以保留。该酶原的激活肽似乎与其他哺乳动物胰腺丝氨酸蛋白酶的激活肽无关。正如外分泌分泌酶合成部位所预期的那样，弹性蛋白酶I的mRNA定位于腺泡细胞的粗面内质网中。大鼠弹性蛋白酶II的mRNA长度为910个核苷酸，加上一个聚腺苷酸尾，编码一个含271个氨基酸的前酶原。其氨基酸序列与猪弹性蛋白酶1的关系更为密切（序列同一性为58%），而与其他胰腺丝氨酸蛋白酶的关系则较弱（序列同一性为33 - 39%）。基于定义底物结合裂隙的关键氨基酸残基对底物偏好性的预测与哺乳动物胰腺弹性蛋白酶2所观察到的广泛特异性一致。其激活肽与胰凝乳蛋白酶原的激活肽相似，并保留了一个N端半胱氨酸，可与一个内部保守的半胱氨酸残基形成二硫键。
