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肽类激素的发现过程,大多是先观察到粗的组织提取物中具有生物学活性,其次,进一步用生物学方法分离提纯粗制品,得到纯品激素,再后,确定激素分子结构。晚近,瑞典生化学家 Mutt 与 Tatemoto 等根据许多肽类激素都含有 C-端酰胺结构这一特性,独具匠心,设计出一种寻找肽类激素的化学新方法。即在组织提取物中先找寻含有 C-端酰胺结构的肽节段,然后用酶学方法测出 C-端及 N-端的氨基酸残基序列,最后,确定激素的分子结构。这种创造性工作,为探寻新的肽类激素开辟了广阔的道路。他们用这种方法,已经在猪的上段小肠中发现了几种以前不为人所知的肽类新激素。其中有两个,即组异肽和酪酪肽,皆是在提纯胰泌素时获得的副产品中找寻到的。组异肽(The peptide with N-terminal histidine and C-terminal isoleucine,简称 PHI),含有27个氨基酸残基。其 C-端序列为亮-异亮-NH_2,N-端序列为组-丙-门冬-甘-缬-苯丙-苏-,与胰泌素、血管活性肠肽(VIP)、胰高血糖素、肠抑胃肽(GIP)相似,属于胰泌素-胰高血糖素家族。初步观察到,它
Peptide hormones found in most of the first observation of crude tissue extracts with biological activity, followed by further biological separation and purification of crude products, pure hormones, and then determine the hormone molecular structure. Recently, the Swedish biochemists Mutt and Tatemoto, based on the fact that many peptide hormones contain a C-terminal amide structure, have their own unique ingenuity in designing a new chemical method for searching for peptide hormones. That is, first in the tissue extract to find C-terminal amide structure of the peptide segment, and then enzymatically measured C-terminal and N-terminal amino acid residue sequence, and finally, to determine the molecular structure of the hormone. This creative work opens the way for new peptide hormones. Using this method, they have discovered several new, unknown peptide neohormones in the upper intestine of pigs. Two of them, the group of isopeptides and casein peptides, are found in by-products obtained when purifying secretin. The peptide with N-terminal histidine and C-terminal isoleucine (PHI for short) contains 27 amino acid residues. The sequence of C-terminal is bright-isole-NH-2, the N-terminal sequence is asparagine, serotonin, vasopressin, Glucagon, gastrointestinal inhibitory peptide (GIP) is similar to the secretin - glucagon family. Preliminary observation, it