Mindroiu T, Carretero O A, Proud D, Walz D, Scicli A G
Hypertension Research Division, Henry Ford Hospital, Detroit, MI.
Biochem Biophys Res Commun. 1988 Apr 29;152(2):519-26. doi: 10.1016/s0006-291x(88)80068-8.
Recently, we isolated a new kinin from human urine and tentatively identified it as [Ala3]-Lys-bradykinin. However, there were inconsistencies between the properties of the naturally occurring new kinin and synthetic [Ala3]-Lys-bradykinin. In the present work, we determined whether the new kinin was released from human plasma kininogen, and further investigated the structure of the new kinin. After incubation of plasma (n = 6) with human urinary kallikrein, kinins were separated by HPLC and measured by RIA. The new kinin and Lys-bradykinin were found representing 23 +/- 3 and 76 +/- 6%, respectively, of total kinins released (2.0 +/- 0.4 micrograms/ml). The new kinin was also released from both purified low- and high-molecular-weight kininogens, representing 40-42% of total kinins released. Amino acid sequencing and composition analysis indicated that the structure of the new kinin was [Hyp3]-Lys-bradykinin (Lys-Arg-Pro-Hyp-Gly-Phe-Ser-Pro-Phe-Arg) and not [Ala3]-Lys-bradykinin. We conclude that an important proportion of human kininogens contain hydroxyproline instead of proline in position three of the bradykinin moiety.
最近，我们从人尿中分离出一种新的激肽，并初步鉴定为[丙氨酸3]-赖氨酸-缓激肽。然而，天然存在的新激肽与合成的[丙氨酸3]-赖氨酸-缓激肽的性质之间存在不一致。在本研究中，我们确定了这种新激肽是否从人血浆激肽原中释放出来，并进一步研究了新激肽的结构。将血浆（n = 6）与人尿激肽释放酶孵育后，通过高效液相色谱法分离激肽，并通过放射免疫分析法进行测定。发现新激肽和赖氨酸-缓激肽分别占释放的总激肽的23±3%和76±6%（2.0±0.4微克/毫升）。新激肽也从纯化的低分子量和高分子量激肽原中释放出来，占释放的总激肽的40 - 42%。氨基酸测序和组成分析表明，新激肽的结构是[羟脯氨酸3]-赖氨酸-缓激肽（赖氨酸-精氨酸-脯氨酸-羟脯氨酸-甘氨酸-苯丙氨酸-丝氨酸-脯氨酸-苯丙氨酸-精氨酸），而不是[丙氨酸3]-赖氨酸-缓激肽。我们得出结论，相当一部分人激肽原在缓激肽部分的第三位含有羟脯氨酸而非脯氨酸。
