Extraction and immunochemical characterization of cholecystokinin-like peptides from pig and rat brain.
Extraction and immunochemical characterization of cholecystokinin-like peptides from pig and rat brain.
复制标题
猪和大鼠脑中胆囊收缩素样肽的提取和免疫化学表征。
DOI：
10.1073/pnas.78.6.3892
复制
发表时间：
1981
影响因子：
11.1
通讯作者：
R. Yalow
中科院分区：
文献类型：
--
作者：
S. Ryder;J. Eng;E. Straus;R. Yalow
在大鼠和猪脑中发现了两大类免疫反应活性的CCK：(1)大的碱性多肽(大的iCCK)在大小和电荷上类似于猪的33个氨基酸(PCCK33)；(2)小的酸性多肽(小的iCCK)类似CCK的COOH末端片段。沸腾0.1M盐酸最大限度地提取大的iCCK；沸腾0.1M的NaOH最大限度地提取小的iCCK。这些萃取剂去除的激素形式的差异不太可能是由于提取过程中的酶转化造成的。Sephadex G-50上的分级和淀粉凝胶电泳与放射免疫分析使用了三种不同特异性的抗血清--(I)针对pCCK33的NH2末端，(Ii)用COOH末端片段CCK8免疫产生的，(Iii)通过COOH末端片段CCK4免疫产生的--与大的iCCK的主要部分可能代表具有COOH末端延伸的完整的CCK的假设一致，就像最近对胃泌素所建议的那样，胃泌素是一种具有与CCK4相同的COOH末端五肽的分子。
Two major classes of immunoreactive cholecystokinin peptides (iCCK) have been identified in rat and pig brains: (i) large basic peptides (big iCCK) resembling the 33-amino acid porcine cholecystokinin (pCCK33) in size and charge; (ii) small acidic peptides (small iCCK) resembling the COOH-terminal fragments of CCK. Boiling 0.1 M HCl maximally extracts big iCCK; boiling 0.1 M NaOH maximally extracts small iCCK. The differences in hormonal forms removed by these extractants are not likely to be due to enzymatic conversion during the extraction procedures. Fractionation on Sephadex G-50 and starch gel electrophoresis combined with radioimmunoassay using three antisera of different specificities--(i) directed towards the NH2 terminus of pCCK33, (ii) produced by immunization with COOH-terminal fragment CCK8, (iii) produced by immunization with COOH-terminal fragment CCK4--are consistent with the hypothesis that a major fraction of big iCCK may represent intact cholecystokinin with a COOH-terminal extension, as has recently been suggested for gastrin, a molecule having a COOH-terminal pentapeptide identical with that of cholecystokinin.