IN-VITRO PROCESSING OF PROOPIOMELANOCORTIN BY RECOMBINANT PC1 (SPC3)
IN-VITRO PROCESSING OF PROOPIOMELANOCORTIN BY RECOMBINANT PC1 (SPC3)
复制标题
DOI：
10.1210/en.135.3.854
复制
发表时间：
1994-09-01
期刊：
影响因子：
4.8
通讯作者：
BIRCH, NP
中科院分区：
文献类型：
--
作者：
FRIEDMAN, TC;LOH, YP;BIRCH, NP
激素原转化酶PC 1（SPC 3）和PC 2是能够加工神经肽前体的枯草杆菌蛋白酶样丝氨酸蛋白酶。在共转染实验中，其他研究者发现PC 1和PC 2可以将POMC加工成合适的肽产物。在这项研究中，重组大鼠PC 1在小鼠L-细胞系中稳定表达并部分纯化。小鼠POMC被重组PC 1切割，产生ACTH中间体、ACTH、连接肽的ACTH、连接肽、16-千道尔顿N-POMC、N-POMC-（1-74）和β-促脂素。还发现重组PC 1将ACTH裂解为ACTH-（1-15）和将牛N-POMC-（1-77）裂解为γ（3）MSH。裂解的最适pH为6.0。我们的结论是，重组PC 1是能够在体外加工POMC在所有配对的碱性残基，除了Lys-Arg和Lys-Lys的β-促脂素和β-内啡肽，分别。这在体外研究表明，更一般的特异性重组PC 1配对和四碱基残基的POMC比以前发现的共转染实验。其他细胞调节机制可能在限制垂体前叶中体内POMC的加工中发挥作用，其中γ（3）MSH和α MSH未发现显著量。
The prohormone convertases, PC1 (SPC3) and PC2, are subtilisin-like serine proteases capable of processing neuropeptide precursors. In cotransfection experiments, other investigators have found that PC1 and PC2 can process POMC to appropriate peptide products. In this study, recombinant rat PC1 was stably expressed in a mouse L-cell line and partially purified. Mouse POMC was cleaved by recombinant PC1 to generate ACTH intermediates, ACTH, ACTH linked to joining peptide, joining peptide, 16-kilodalton N-POMC, N-POMC-(1-74), and beta-lipotropin. Recombinant PC1 was also found to cleave ACTH to ACTH-(1-15) and bovine N-POMC-(1-77) to gamma(3)MSH. The pH optimum of the cleavages was 6.0. We conclude that recombinant PC1 is capable of processing POMC in vitro at all of the paired basic residues, with the exception of Lys-Arg and Lys-Lys in beta-lipotropin and beta-endorphin, respectively. This in vitro study showed a more general specificity of recombinant PC1 for paired and tetrabasic residues of POMC than was previously found in cotransfection experiments. Other cellular regulatory mechanisms probably play a role in limiting the processing of POMC in vivo in the anterior pituitary, where gamma(3)MSH and alpha MSH are not found in significant amounts.