人体内超过50%的蛋白质为糖蛋白，蛋白质的糖基化对蛋白质的稳定性、免疫调节、信号传导和生物活性有很大的影响。随着糖生物学、基因工程技术的发展，对于糖蛋白的研究已经渗透到免疫，病理，神经等各个交叉学科。由于技术的局限，基因工程技术无法获得糖链化学均一的糖蛋白。利用合成的方法得到精确结构的糖蛋白，糖肽分子，可以让生物学家更好的理解糖蛋白结构与功能间的关系，以发展出更好的药物。干扰素伽玛作为唯一的II型干扰素成员，在免疫调节、肿瘤治疗、抗病毒领域都有不可替代的作用，对其化学合成具有重要的科学意义。.　项目主要研究内容包括：.　1）复杂N型糖链的获取与合成;　2）发展新方法，快速简洁的合成复杂N型糖肽；3）以合成含有化学均一糖链的IFN-γ为目标，同时发展出高效的方法合成糖树状分子修饰的IFN-γ，并与重组IFN-γ进行免疫活性比较，增加对IFN-γ糖链功能的了解。

Carbohydrate on proteins plays important roles in many biological processes, such as protein cell-cell interaction, signal translation and bioactivity. Moreover, glycans appear to stabilize protein, help in folding by protecting proteins from proteolysis. Unfortunately, numerous investigations have been complicated by the difficulties in obtaining homogeneous glycoproteins by genetic engineering methods.This obstacle arises from that glycoproteins, which were biosynthesized through nonspecific post-translational glycosylation, are typically obtained as mixtures of difficult to separate glycoforms.. Chemical synthesis of homogeneous glycoprotein, by affording the precise structure molecule, will facilitate the study about relationship between the structure and function of glycoproteins. . Interferon gamma, is a dimerized cytokine, which is the only member of type II interferons. Interferon gamma shows activities about immunity, antiviral and antitumor, especially playing an important role as an immunomodulator. It's quite important to get homogeneous interferon gamma. . This proposal includes:.1) Chemical synthesis of complex N-glycan; 2) Develop high efficient method to synthesize N-glycan; 3) Synthesizing interferon gamma with homogeneous oligosaccharide, addressing the question about it's carbohydrate structure and functions relationship.