The function of peptidylarginine deiminase expressed in the retina of chicken

肽基精氨酸脱亚胺酶是一种翻译后修饰酶，能以钙离子依赖的方式催化蛋白质结合的精氨酸转化为瓜氨酸。尽管PADI基因在脊椎动物中广泛保守，但它们在鸡中的功能却鲜为人知。我们克隆并测序了三个鸡PADI基因的cDNAs，并分析了它们在不同组织中的蛋白表达。免疫印迹分析表明，鸡PAD1和PAD3存在于包括视网膜在内的几个中枢神经系统组织的细胞中。鸡PAD1和PAD3重组蛋白的催化活性需要钙离子作为必需的辅因子。这两种重组蛋白对合成的精氨酸衍生物表现出相似的底物特异性。我们得出结论，鸡PAD1和PAD3可能在神经系统中发挥特定的作用，但在正常生理条件下，鸡PAD2可能不起作用。

Peptidylarginine deiminase is a post-translational modification enzyme that catalyzes the conversion of protein-bound arginine to citrulline in a calcium ion dependent manner. Although PADI genes are widely conserved among vertebrates, their function in the chicken is poorly understood. We cloned and sequenced three chicken PADI cDNAs and analyzed the expression of their proteins in various tissues. Immunoblotting analysis showed that chicken PAD1 and PAD3 were present in cells of several central neuron system tissues including the retina. The chicken PAD1 and PAD3 recombinant proteins required calcium ions as an essential cofactor for their catalytic activity. The two recombinant proteins showed similar substrate specificities toward synthetic arginine derivatives. We conclude that chicken PAD1 and PAD3 might play specific roles in the nervous system, but that chicken PAD2 might not be functional under normal physiological conditions.