Department of Chemistry, Lehigh University, 6 E. Packer Ave., Bethlehem, PA 18015, USA.
Chembiochem. 2013 May 27;14(8):963-7. doi: 10.1002/cbic.201300173. Epub 2013 May 2.
The post-translational modifications of histone proteins are highly diverse and dynamic processes. It is becoming increasingly evident that modifying histone proteins can have a direct influence on both cellular homeostasis and disease states. Protein arginine deiminase 4 (PAD4) is an enzyme that converts peptidyl-arginine to citrulline. The overexpression of PAD4 has been found in numerous types of human cancer and autoimmune diseases. We report a new, facile, fluorescence-based assay for the detection of PAD4 activity that exploits the substrate specificity of trypsin to monitor the citrullination reaction carried out by PAD4 based on the fact that, upon citrullination, the positively charged arginine side chain is converted to the neutral citrulline. We show that the assay can be performed rapidly with readily available reagents and that it responds accordingly to a known PAD4 inhibitor.
组蛋白蛋白质的翻译后修饰是高度多样化和动态的过程。越来越明显的是，修饰组蛋白蛋白质可以直接影响细胞内稳态和疾病状态。蛋白精氨酸脱亚氨酶 4（PAD4）是一种将肽精氨酸转化为瓜氨酸的酶。在许多类型的人类癌症和自身免疫性疾病中都发现了 PAD4 的过表达。我们报告了一种新的、简便的基于荧光的 PAD4 活性检测方法，该方法利用了胰蛋白酶的底物特异性来监测 PAD4 进行的瓜氨酸化反应，其依据是，在瓜氨酸化后，带正电荷的精氨酸侧链被转化为中性的瓜氨酸。我们表明，该测定法可以使用现成的试剂快速进行，并且可以相应地响应已知的 PAD4 抑制剂。
