Mindroiu T, Scicli G, Perini F, Carretero O A, Scicli A G
J Biol Chem. 1986 Jun 5;261(16):7407-11.
The types of kinins excreted in fresh urine of dogs, rats, and humans were compared. Urinary kinins were separated by reverse-phase (C18) high performance liquid chromatography and quantitated by radioimmunoassay using an antibody directed against the COOH-terminal region of the peptide. Kinins were found in the following proportions: 53 +/- 3% bradykinin, 23 +/- 4% Lys-bradykinin, and 13 +/- 7% des-Arg1-bradykinin in dog urine; 67 +/- 6% bradykinin, 6 +/- 3% Lys-bradykinin, and 10 +/- 3% des-Arg1-bradykinin in rat urine; and 12 +/- 4% bradykinin, 30 +/- 3% Lys-bradykinin, 2 +/- 1% des-Arg1-bradykinin, and 41 +/- 3% unknown kinin in human urine. The unknown kinin was purified from a pool of human urine. Amino acid sequencing revealed a structure similar to Lys-bradykinin except that proline in position 4 was replaced by alanine ([Ala3]Lys-bradykinin). Synthetic and endogenous [Ala3]Lys-bradykinins had similar high performance liquid chromotography elution volumes and both had vasodilator activity and contracted the rat uterus. Human urinary kallikrein incubated with semipurified human low molecular weight kininogen released 76% of the total kinins as Lys-bradykinin, 7% as bradykinin, and 17% as [Ala3]Lys-bradykinin. In contrast, rat urinary kallikrein released 86% bradykinin, 18% Lys-bradykinin, and negligible amounts of [Ala3]Lys-bradykinin. The study revealed the presence of a new kinin, [Ala3]Lys-bradykinin, in human urine and it also proves that the types of kinins generated intrarenally are species-dependent.
对狗、大鼠和人类新鲜尿液中排出的激肽类型进行了比较。尿激肽通过反相（C18）高效液相色谱法分离，并用针对该肽COOH末端区域的抗体通过放射免疫测定法定量。发现狗尿中激肽的比例如下：缓激肽53±3%，赖氨酸缓激肽23±4%，脱-精氨酸1-缓激肽13±7%；大鼠尿中：缓激肽67±6%，赖氨酸缓激肽6±3%，脱-精氨酸1-缓激肽10±3%；人类尿中：缓激肽12±4%，赖氨酸缓激肽30±3%，脱-精氨酸1-缓激肽2±1%，未知激肽41±3%。从人尿池中纯化出未知激肽。氨基酸测序显示其结构与赖氨酸缓激肽相似，只是第4位的脯氨酸被丙氨酸取代（[丙氨酸3]赖氨酸缓激肽）。合成的和内源性的[丙氨酸3]赖氨酸缓激肽具有相似的高效液相色谱洗脱体积，且都具有血管舒张活性并能使大鼠子宫收缩。用半纯化的人低分子量激肽原与人尿激肽释放酶一起孵育，释放出的总激肽中76%为赖氨酸缓激肽，7%为缓激肽，17%为[丙氨酸3]赖氨酸缓激肽。相比之下，大鼠尿激肽释放酶释放出86%的缓激肽，18%的赖氨酸缓激肽，[丙氨酸3]赖氨酸缓激肽的量可忽略不计。该研究揭示了人尿中存在一种新的激肽，即[丙氨酸3]赖氨酸缓激肽，并且还证明了肾内产生的激肽类型具有种属依赖性。
