Wang Y, Youson J H, Conlon J M
Regulatory Peptide Center, Creighton University Medical School, Omaha, NE 68178.
Regul Pept. 1993 Aug 13;47(1):33-9. doi: 10.1016/0167-0115(93)90270-i.
With the exception of the Agnatha (lampreys and hagfishes), somatostatin-14 is the predominant molecular form of somatostatin in the pancreas of species from all classes of vertebrates yet studied. The pancreas of the holostean fish, Amia calva (bowfin; order Amiiformes) contained somatostatin-like immunoreactivity that was resolved by reversed phase HPLC in two components. The primary structure of the more abundant peptide (somatostatin-26) was established as: Ser-Ala-Asn-Pro-Ala5-Leu-Ala-Pro-Arg-Glu10-Arg-Lys-Ala-Gly-+ ++Cys15-Lys-Asn-Phe- Phe-Trp20-Lys-Thr-Phe-Thr-Ser25-Cys. This amino acid sequence shows one substitution (Leu for Met at position 6) and two deletions compared with mammalian somatostatin-28. The minor component was identical to somatostatin-14. The data show that the pathway of post-translational processing of prosomatostatin-I in the bowfin pancreas is appreciably different from the corresponding pathway in teleost fish and higher vertebrates.
除了无颌类动物（七鳃鳗和盲鳗）外，生长抑素-14是所有已研究的脊椎动物类群胰腺中生长抑素的主要分子形式。全骨鱼类美洲雀鳝（弓鳍鱼；弓鳍鱼目）的胰腺含有生长抑素样免疫反应性物质，通过反相高效液相色谱法可将其分离为两个组分。含量较高的肽（生长抑素-26）的一级结构确定为：Ser-Ala-Asn-Pro-Ala5-Leu-Ala-Pro-Arg-Glu10-Arg-Lys-Ala-Gly-+ ++Cys15-Lys-Asn-Phe-Phe-Trp20-Lys-Thr-Phe-Thr-Ser25-Cys。与哺乳动物生长抑素-28相比，该氨基酸序列显示有一个取代（第6位的Leu取代Met）和两个缺失。次要组分与生长抑素-14相同。数据表明，弓鳍鱼胰腺中前生长抑素-I的翻译后加工途径与硬骨鱼和高等脊椎动物中的相应途径明显不同。
