Biochemistry & Proteomics Group, Department of Chemistry & Biomolecular Science, Clarkson University, Potsdam, NY, USA.
Biotechnol Appl Biochem. 2012 Nov-Dec;59(6):445-50. doi: 10.1002/bab.1046. Epub 2012 Nov 20.
Tumor differentiation factor (TDF) is a 17 kDa protein produced by the pituitary and secreted into the bloodstream, with no definitive function and incomplete characterization. TDF has the following four cysteine (Cys) residues: Cys17, Cys70, Cys97, and Cys98. To understand the function of TDF, we (1) overexpressed and characterized recombinant TDF (rTDF); (2) investigated native, secreted TDF; and (3) assessed potential disulfide connectivities using molecular modeling. Our results from Western blotting (WB) experiments suggest that rTDF is mostly expressed as insoluble, monomeric, and dimeric forms. Mass spectrometry analysis of the overexpressed rTDF identified a peptide that is a part of TDF protein. WB of the native, secreted TDF detected it as a 50 kDa band. In addition, investigation of TDF by molecular modeling suggests that the Cys residues may form disulfide bridges between Cys17-Cys98 and Cys70-Cys17.
肿瘤分化因子（TDF）是由垂体产生并分泌到血液中的一种 17kDa 蛋白，其功能不明确，特征不完全。TDF 有以下四个半胱氨酸（Cys）残基：Cys17、Cys70、Cys97 和 Cys98。为了了解 TDF 的功能，我们（1）过表达并表征重组 TDF（rTDF）；（2）研究天然的、分泌型的 TDF；（3）使用分子建模评估潜在的二硫键连接。我们的 Western blot（WB）实验结果表明，rTDF 主要以不溶性、单体和二聚体形式表达。对过表达的 rTDF 的质谱分析鉴定出一个是 TDF 蛋白的一部分的肽。对天然、分泌型 TDF 的 WB 检测到它是 50kDa 条带。此外，通过分子建模研究 TDF 表明，Cys 残基可能在 Cys17-Cys98 和 Cys70-Cys17 之间形成二硫键。
