Ben-Avram C M, Shively J E, Shadduck R K, Waheed A, Rajavashisth T, Lusis A J
Proc Natl Acad Sci U S A. 1985 Jul;82(13):4486-9. doi: 10.1073/pnas.82.13.4486.
We report the amino acid composition, the NH2-terminal sequence, and the tryptic map by HPLC for murine L-cell colony-stimulating factor 1 (CSF-1). CSF-1 purified by affinity chromatography was S-carboxymethylated under denaturing conditions and subjected to sequence microanalysis. CSF-1 contains four or five cysteine residues per subunit and approximately 30-40% carbohydrate by weight. Three contiguous cysteine residues were located in the NH2-terminal sequence. An additional two cysteine residues were located on the tryptic map. Previous studies as well as immunoblotting studies reported here suggest that sulfhydryl bridging plays a major role in maintaining the conformation of the protein. Carbohydrate was located on two tryptic fragments. The findings of a single NH2-terminal sequence in high yield and a relatively simple tryptic map (15 major peptides) suggest that CSF-1 contains two identical subunits. The NH2-terminal sequence of CSF-1 has only limited homology to insulin or insulin-like hormones but no homology with granulocyte/macrophage-CSF or interleukin 3.
我们报道了小鼠L细胞集落刺激因子1（CSF-1）的氨基酸组成、氨基末端序列以及通过高效液相色谱法得到的胰蛋白酶图谱。通过亲和层析纯化的CSF-1在变性条件下进行S-羧甲基化，并进行序列微量分析。CSF-1每个亚基含有四个或五个半胱氨酸残基，按重量计约含30-40%的碳水化合物。三个相邻的半胱氨酸残基位于氨基末端序列中。另外两个半胱氨酸残基位于胰蛋白酶图谱上。此前的研究以及本文报道的免疫印迹研究表明，巯基桥接在维持蛋白质构象方面起主要作用。碳水化合物位于两个胰蛋白酶片段上。高产量的单一氨基末端序列以及相对简单的胰蛋白酶图谱（15个主要肽段）的研究结果表明，CSF-1含有两个相同的亚基。CSF-1的氨基末端序列与胰岛素或胰岛素样激素仅有有限的同源性，但与粒细胞/巨噬细胞集落刺激因子或白细胞介素3没有同源性。
