Tonon M C, Desrues L, Lazure C, Jenks B G, Chrétien M, Vaudry H
URA CNRS 650, Unité Affiliée à l'INSERM, Université de Rouen, Mont-Saint-Aignan, France.
Life Sci. 1989;45(13):1155-61. doi: 10.1016/0024-3205(89)90503-1.
The structure of alpha-melanocyte-stimulating hormone (alpha-MSH) has been determined in the pars intermedia of the frog Rana ridibunda. Pulse-chase labeling of frog neurointermediate lobes with selective amino acids revealed that the composition of frog alpha-MSH is similar to that of alpha-MSH from all mammalian species yet studied. Tryptic mapping of nexly synthetized alpha-MSH generated two fragments with the following amino acid composition: (T1) Trp, Pro, Lys, Gly, Val and (T2) Tyr, Arg, Phe, His, Ser, Glu. Concurrently, alpha-MSH was purified from 100 neurointermediate lobes to apparent homogeneity by reverse-phase HPLC. The sequence of the peptide determined by automated Edman degradation was Ser-Tyr-Ser-Met-Glu-His-Phe-Arg-Trp-Gly-Lys-Pro-Val. The structure of frog alpha-MSH is thus identical to mammalian des-N alpha-acetyl alpha-MSH and differs from the sequence of toad (Xenopus laevis) alpha-MSH only by the first residue (Ser instead of Ala). These results confirm that the sequence of alpha-MSH has been highly preserved during evolution.
已在泽蛙的垂体中间部确定了α-黑素细胞刺激素（α-MSH）的结构。用选择性氨基酸对蛙神经中间叶进行脉冲追踪标记显示，蛙α-MSH的组成与所有已研究的哺乳动物物种的α-MSH相似。对新合成的α-MSH进行胰蛋白酶图谱分析产生了两个片段，其氨基酸组成如下：（T1）Trp、Pro、Lys、Gly、Val和（T2）Tyr、Arg、Phe、His、Ser、Glu。同时，通过反相高效液相色谱法从100个神经中间叶中纯化α-MSH至表观均一性。通过自动埃德曼降解法测定的肽序列为Ser-Tyr-Ser-Met-Glu-His-Phe-Arg-Trp-Gly-Lys-Pro-Val。因此，蛙α-MSH的结构与哺乳动物的去Nα-乙酰基α-MSH相同，并且与蟾蜍（非洲爪蟾）α-MSH的序列仅在第一个残基上不同（Ser而不是Ala）。这些结果证实了α-MSH的序列在进化过程中得到了高度保留。
