猪垂体中的α-黑素细胞刺激素前体
alpha-Melanocyte-stimulating-hormone precursors in the pig pituitary.
作者信息
Fenger M
出版信息
Biochem J. 1986 May 1;235(3):715-22. doi: 10.1042/bj2350715.
The occurrence of intermediates from the processing of ACTH-(1-39) [adrenocorticotropic hormone-(1-39)] to alpha-melanocyte-stimulating hormone was investigated in normal pig pituitaries by the use of sensitive and specific radioimmunoassays for ACTH-(1-13), ACTH-(1-14), ACTH-(1-13)-NH2 and ACTH-(1-39). Fractionation by reverse-phase h.p.l.c. revealed ACTH(1-17) and their acetylated analogues. The intermediate lobe contained NO-diacetyl-ACTH-(1-13)-NH2, N-acetyl-ACTH-(1-13)-NH2 and ACTH-(1-13)-NH2. In addition, the corresponding ACTH-(1-14) peptides (the glycine-extended precursor of the amidated peptides) were detected in lower amounts in both the intermediate lobe and the anterior lobe. ACTH-(1-17), ACTH-(1-13) and their acetylated analogues could not be detected in the anterior lobe or the intermediate lobe. The results suggest that an endopeptidase initially cleaves ACTH-(1-39) at the Lys-16-Arg-17 bond. ACTH-(1-16) is then processed by a pituitary carboxypeptidase to ACTH-(1-14) and ACTH-(17-39) by the aminopeptidase to ACTH-(18-39).
利用针对促肾上腺皮质激素（ACTH）-(1 - 13)、ACTH-(1 - 14)、ACTH-(1 - 13)-NH₂和ACTH-(1 - 39)的灵敏且特异的放射免疫分析法，研究了正常猪垂体中从促肾上腺皮质激素-(1 - 39)加工生成α - 黑素细胞刺激素过程中中间产物的情况。通过反相高效液相色谱法分离，发现了ACTH(1 - 17)及其乙酰化类似物。中间叶含有二乙酰化 - ACTH-(1 - 13)-NH₂、N - 乙酰化 - ACTH-(1 - 13)-NH₂和ACTH-(1 - 13)-NH₂。此外，在中间叶和前叶中均检测到了含量较低的相应ACTH-(1 - 14)肽（酰胺化肽的甘氨酸延伸前体）。在前叶或中间叶中未检测到ACTH-(1 - 17)、ACTH-(1 - 13)及其乙酰化类似物。结果表明，一种内肽酶最初在赖氨酸 - 16 - 精氨酸 - 17键处切割ACTH-(1 - 39)。然后，ACTH-(1 - 16)由垂体羧肽酶加工生成ACTH-(1 - 14)，由氨肽酶加工生成ACTH-(17 - 39)进而生成ACTH-(18 - 39)。
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