Björk P, Ohlsson K
Department of Surgical Pathophysiology, University of Lund, Malmö General Hospital.
Biol Chem Hoppe Seyler. 1990 Jul;371(7):595-601. doi: 10.1515/bchm3.1990.371.2.595.
Cathepsin G was purified by single-step cation-exchange chromatography from rat polymorphonuclear leukocytes, obtained from the peritoneal cavity after induction of a mild peritonitis. The 26 N-terminal amino acids were determined and showed 73% identity to those of human cathepsin G. Total amino-acid composition demonstrated a high degree of basic amino acids in accordance with its high affinity for the cationic-exchange gel medium. The protein was found to be a glycoprotein with a glucosamine content of 7.4% of the calculated Mr28,900. On SDS/polyacrylamide-gel electrophoresis the protein showed a Mr of 28,400. It migrated as two bands in a gradient SDS/polyacrylamide-gel indicating isoforms. The pH optimum for the proteinase was determined to be 8.0-8.5 using Suc-Ala-Ala-Pro-Phe-Nan as substrate (Suc = 3-carboxypropionyl; Nan = 4-nitroanilide). Km and Kcat/Km values for Suc-Ala-Ala-Pro-Phe-Nan were 0.86mM and 280M-1S-1 and for Suc-Phe-Leu-Phe-Nan 0.24mM and 3600M-1S-1, respectively.
组织蛋白酶G通过一步阳离子交换色谱法从大鼠多形核白细胞中纯化得到，这些细胞取自轻度腹膜炎诱导后的腹腔。测定了其26个N端氨基酸，结果显示与人类组织蛋白酶G的N端氨基酸有73%的同源性。总氨基酸组成表明其碱性氨基酸含量高，这与其对阳离子交换凝胶介质的高亲和力相符。该蛋白质被发现是一种糖蛋白，其氨基葡萄糖含量占计算分子量28,900的7.4%。在SDS/聚丙烯酰胺凝胶电泳中，该蛋白质的分子量为28,400。在梯度SDS/聚丙烯酰胺凝胶中它以两条带迁移，表明存在同工型。以琥珀酰 - 丙氨酰 - 丙氨酰 - 脯氨酰 - 苯丙氨酰 - 对硝基苯胺（Suc = 3 - 羧基丙酰基；Nan = 4 - 硝基苯胺）为底物时，该蛋白酶的最适pH值为8.0 - 8.5。琥珀酰 - 丙氨酰 - 丙氨酰 - 脯氨酰 - 苯丙氨酰 - 对硝基苯胺的Km值和Kcat/Km值分别为0.86mM和280M⁻¹S⁻¹，琥珀酰 - 苯丙氨酰 - 亮氨酰 - 苯丙氨酰 - 对硝基苯胺的Km值和Kcat/Km值分别为0.24mM和3600M⁻¹S⁻¹。
