Mazzacoratti M da G, Sampaio M U, Duarte P C, Sampaio C A
Adv Exp Med Biol. 1986;198 Pt A:389-96. doi: 10.1007/978-1-4684-5143-6_53.
Proteases which inactivate bradykinin were partially purified from the fresh exsanguinated liver of rat, man, dog, guinea-pig, chicken, frog and snake. The enzymes which are present in the soluble fraction of the liver homogenates, were prepared by DEAE-cellulose chromatography, in 0.025 M tris-HCl, pH 7.4. The peptidase activity was eluted with 0.09 M KCl; and further purification was achieved by gel-filtration in Sephadex G-150. The kininases are present in the same range of activity in all studied preparations, and final specific activities are also comparable. The molecular weight of the enzymes, as determined by gel filtration, are in the range of 70,000-100,000. All preparations were completely inhibited by 10 mM PMSF and 1 mM Tos-PheCh2Cl; 10 microM 2-mercaptoethanol, and 1 mM Tos-LysCH2Cl do not affect the enzymatic activity. The major site for the cleavage of bradykinin is the Phe5-Ser6 peptide bond. The serine-peptidase is found in the liver of all vertebrates so far studied.
从大鼠、人、狗、豚鼠、鸡、青蛙和蛇刚放血的新鲜肝脏中部分纯化了使缓激肽失活的蛋白酶。这些存在于肝脏匀浆可溶部分的酶，是通过在pH 7.4的0.025 M三羟甲基氨基甲烷 - 盐酸缓冲液中用DEAE - 纤维素色谱法制备的。肽酶活性用0.09 M氯化钾洗脱；通过在葡聚糖G - 150中进行凝胶过滤进一步纯化。在所有研究的制剂中，激肽酶的活性范围相同，最终的比活性也相当。通过凝胶过滤测定，这些酶的分子量在70,000 - 100,000范围内。所有制剂都被10 mM苯甲基磺酰氟和1 mM甲苯磺酰 - 苯丙氨酸氯甲基酮完全抑制；10 microM 2 - 巯基乙醇和1 mM甲苯磺酰 - 赖氨酸氯甲基酮不影响酶活性。缓激肽的主要裂解位点是苯丙氨酸5 - 丝氨酸6肽键。到目前为止，在所有已研究的脊椎动物肝脏中都发现了丝氨酸肽酶。
