Egorova T P, Makevnina L G, Paskhina T S
Biokhimiia. 1975 Jan-Feb;40(1):158-65.
Highly purified kininogen preparation with the activity of 16-18 int. units per mg was isolated from rabbit blood serum. Its molecular weight was estimated to be 54 000 by gel filtration through Sephadex G-200. Leucine was identified as N-terminal amino acid by the dansylation method. Rabbit kininogen consists of 394 amino acid residues (except tryptophane). Amino acid composition of kininogen is characterized by a high content of dicarbonic amino acids, proline and by a low content of methionine. Kininogen molecule does not contain SH-groups. 13.1-13.5 SH-groups were found in kininogen after the reduction of S-S bonds with beta-mercaptoethanol in the presence of 8 M urea, thus indicating the presence of 6-7 S-S bonds in kininogen molecule. Kininogen group does not occupy C-terminal position in the molecule, because the treatment of the protein with carboxypeptidase B does not change the content of bradykinine in it. Purified kininogen preparation is a substrate for kallikrein from rabbit blood plasma, human saliva and trypsin. Unlike trypsin, kallikreines from human blood plasma and saliva release kinines from kininogen with reduced S-S bonds. Under spontaneous reoxidation of reduced S-S bonds up to 90%, substate properties of kininogen for tripsin recover only by 50%. Rabbit kininogen is similar to beef kininogen II in its molecular weight, amino acid composition and the number of S-S bonds.
从兔血清中分离出了活性为每毫克16 - 18国际单位的高度纯化激肽原制剂。通过Sephadex G - 200凝胶过滤法估计其分子量为54000。采用丹磺酰化法鉴定亮氨酸为N端氨基酸。兔激肽原由394个氨基酸残基组成（色氨酸除外）。激肽原的氨基酸组成特点是二羧基氨基酸、脯氨酸含量高，蛋氨酸含量低。激肽原分子不含SH基团。在8M尿素存在下用β - 巯基乙醇还原S - S键后，在激肽原中发现13.1 - 13.5个SH基团，这表明激肽原分子中存在6 - 7个S - S键。激肽原基团在分子中不占据C端位置，因为用羧肽酶B处理该蛋白质不会改变其中缓激肽的含量。纯化的激肽原制剂是兔血浆、人唾液中的激肽释放酶和胰蛋白酶的底物。与胰蛋白酶不同，人血浆和唾液中的激肽释放酶能从具有还原S - S键的激肽原中释放激肽。在还原的S - S键自发再氧化达90%时，激肽原对胰蛋白酶的底物特性仅恢复50%。兔激肽原在分子量、氨基酸组成和S - S键数量方面与牛激肽原II相似。
