Shaw C, Murphy R, Thim L, Furness J B, Buchanan K D
Department of Medicine, Queen's University of Belfast, Northern Ireland.
Regul Pept. 1991 Jul 23;35(1):49-57. doi: 10.1016/0167-0115(91)90253-d.
Neurotensin has been isolated from small intestinal extracts of an Australian marsupial, the brush-tailed possum (Trichosurus vulpecula). The primary structure was determined as: pGlu-Leu-His-Val-Asn-Lys-Ala-Arg-Arg-Val-Tyr-Ile-Leu. When compared with bovine neurotensin, marsupial possum neurotensin exhibits four amino acid substitutions. His for Tyr3, Val for Glu4 and Ala for Pro7 are identical with those found in chicken neurotensin. In addition, substitution of Pro10 with Val is unique among all neurotensins sequenced to date. Marsupial possum neurotensin is therefore of unique primary structure, displaying most sequence homology with its avian counterpart. This neurotensin may thus resemble the phylogenetic precursor present at the time of divergence of primitive mammals and birds.
神经降压素是从澳大利亚有袋动物帚尾袋貂（Trichosurus vulpecula）的小肠提取物中分离出来的。其一级结构确定为：焦谷氨酸-亮氨酸-组氨酸-缬氨酸-天冬酰胺-赖氨酸-丙氨酸-精氨酸-精氨酸-缬氨酸-酪氨酸-异亮氨酸-亮氨酸。与牛神经降压素相比，有袋动物袋貂神经降压素存在四处氨基酸替换。组氨酸替换酪氨酸3、缬氨酸替换谷氨酸4以及丙氨酸替换脯氨酸7与在鸡神经降压素中发现的替换相同。此外，脯氨酸10被缬氨酸替换在迄今为止测序的所有神经降压素中是独一无二的。因此，有袋动物袋貂神经降压素具有独特的一级结构，与其鸟类对应物显示出最大的序列同源性。因此，这种神经降压素可能类似于原始哺乳动物和鸟类分化时存在的系统发育前体。
