Yamashita Y, Holst Pedersen J, Stadil F
Peptides. 1987 Jul-Aug;8(4):639-43. doi: 10.1016/0196-9781(87)90038-6.
The extractability of neurotensin (NT) from porcine ileal mucosa was studied by comparison of eight extraction procedures. Tissue content of neurotensin-like immunoreactivity was quantitated and characterized by sequence-specific radioimmunoassays and gel filtration chromatography. Homogenization prior to boiling in extraction solvent produced higher levels of the intact peptide than the reverse procedure. N-terminal immunoreactivity was not influenced by the sequence of these steps. Tissue levels of intact NT were highest after extraction with 2.0 M acetic acid (mean 79.1 pmol/g, N = 6) and lowest with distilled water (mean 6.5 pmol/g, N = 6). The opposite was the case with levels of N-terminal immunoreactivity (mean 55.2 pmol/g and 105.7 pmol/g respectively, N = 6). Recovery experiments with addition of synthetic NT 1-13 and the N-terminal fragment NT 1-8 indicated that these differences could be explained by differences in recovery of intact NT and N-terminal immunoreactive components in tissue. Gel chromatography confirmed that in acetic acid almost only the intact peptide was extracted from ileal mucosa, and showed that after extraction in water or phosphate buffer several N-terminal components were present. The results suggest that a molecular heterogeneity may be present in ileal tissue. If this concept is supported by further studies differential extraction procedures may be needed in the future.
通过比较八种提取方法，研究了猪回肠黏膜中神经降压素（NT）的可提取性。通过序列特异性放射免疫分析和凝胶过滤色谱法对神经降压素样免疫反应性的组织含量进行定量和表征。在提取溶剂中煮沸之前进行匀浆比相反的操作产生更高水平的完整肽。N端免疫反应性不受这些步骤顺序的影响。用2.0 M乙酸提取后完整NT的组织水平最高（平均79.1 pmol/g，N = 6），用蒸馏水提取时最低（平均6.5 pmol/g，N = 6）。N端免疫反应性水平则相反（分别为平均55.2 pmol/g和105.7 pmol/g，N = 6）。添加合成NT 1-13和N端片段NT 1-8的回收率实验表明，这些差异可以用组织中完整NT和N端免疫反应性成分回收率的差异来解释。凝胶色谱法证实，在乙酸中几乎只从回肠黏膜中提取出完整肽，并表明在水或磷酸盐缓冲液中提取后存在几种N端成分。结果表明回肠组织中可能存在分子异质性。如果这一概念得到进一步研究的支持，未来可能需要不同的提取方法。
