Bennett H P, Browne C A, Solomon S
Proc Natl Acad Sci U S A. 1981 Aug;78(8):4713-7. doi: 10.1073/pnas.78.8.4713.
Phosphorylated forms of corticotropin[ACTH (1-39)], corticotropin-like intermediary lobe peptide[CLIP, ACTH (18-39)], and the common precursor for ACTH and beta-lipotropin (beta-LPH) have been identified in extracts of rat pituitaries, 32P-Labeled inorganic phosphate was successfully incorporated into ACTH (1-39), CLIP, and the ACTH/beta-LPH precursor in rat neurointermediary lobe explants and into ACTH (1-39) in isolated rat anterior pituitary cells. After peptidase digestion of the labeled CLIP and ACTH, the radioactive phosphate was recoverable as O-phosphoserine. The serine residue at position 31 was the only amino acid found to be phosphorylated in CLIP and ACTH (1-39). The unphosphorylated forms of both peptides were also synthesized. The demonstration of he incorporation of [32P]phosphate into CLIP, ACTH (1-39), and the ACTH/beta-LPH precursor is consistent with the hypothesis that, within the rat intermediary lobe, phosphorylated CLIP is derived from a phosphorylated form of the common precursor, with phosphorylated ACTH (1-39) acting as a biosynthetic intermediate.
在大鼠垂体提取物中已鉴定出促肾上腺皮质激素[促肾上腺皮质激素（1-39）]、促肾上腺皮质激素样中间叶肽[促肾上腺皮质激素样中间叶肽，促肾上腺皮质激素（18-39）]以及促肾上腺皮质激素和β-促脂素（β-LPH）的共同前体的磷酸化形式。32P标记的无机磷酸盐成功地掺入大鼠神经中间叶外植体中的促肾上腺皮质激素（1-39）、促肾上腺皮质激素样中间叶肽和促肾上腺皮质激素/β-促脂素前体以及分离的大鼠垂体前叶细胞中的促肾上腺皮质激素（1-39）。在对标记的促肾上腺皮质激素样中间叶肽和促肾上腺皮质激素进行肽酶消化后，放射性磷酸盐可作为O-磷酸丝氨酸回收。第31位的丝氨酸残基是在促肾上腺皮质激素样中间叶肽和促肾上腺皮质激素（1-39）中发现的唯一被磷酸化的氨基酸。这两种肽的未磷酸化形式也被合成。[32P]磷酸盐掺入促肾上腺皮质激素样中间叶肽、促肾上腺皮质激素（1-39）和促肾上腺皮质激素/β-促脂素前体的结果与以下假设一致：在大鼠中间叶内，磷酸化的促肾上腺皮质激素样中间叶肽源自共同前体的磷酸化形式，磷酸化的促肾上腺皮质激素（1-39）作为生物合成中间体。
