硫酸乙酰肝素（Heparan Sulfate，HS）是一类由葡萄糖醛酸（GlcUA）/艾杜糖醛酸（IdoUA）与N-乙酰葡萄糖胺（GlcNAc）组成的二糖单位（GlcUA/IdoUAβ/α1-4GlcNAc）经α-1,4糖苷键重复连接而成的硫酸化GAGs。在生物合成中，HS与核心蛋白共价结合形成蛋白聚糖（HS proteoglycans，HSPGs），在细胞表面和细胞外基质中广泛表达；GlcUA可发生差向异构化形成IdoUA，同时在多种硫酸基转移酶的作用下，对HS链中的GlcNAc的N，C6及C3位和GlcUA的C2位进行硫酸化修饰，形成结构高度复杂的HS侧链。与肝素（Heparin，Hep）相比，HS结构更为复杂，具体表现为硫化模式更多样，IdoA含量更低，多糖链更长。HS多糖链大体上可以分成三个部分：NA区，没有经过硫酸化修饰的区域；NS区，该区段内二糖单元中的GlcNAc残基发生了脱乙酰化和硫酸化修饰；NA/NS区段，为NA和NS的混合存在区段，HS中的诸多硫酸化修饰和差向异构化修饰都发生在该区域。HS通过与生长因子、细胞因子、基质蛋白等的相互作用，参与了生长发育和疾病发生等各种生理和病理过程。 Heparan Sulfate (HS) is a class of sulfated GAGs composed of disaccharide units (GlcUA/IdoUA β/α 1-4GlcNAc) composed of glucuronic acid (GlcUA)/iduronic acid (IdoUA) and N-acetylglucosamine (GlcNAc), which are repeatedly linked by α -1,4-glycosidic bonds. In biosynthesis, HS covalently binds to core proteins to form proteoglycans (HSPGs), which are widely expressed on the cell surface and extracellular matrix; GlcUA can undergo differential isomerization to form IdoUA, and under the action of various sulfate transferases, the N, C6, and C3 positions of GlcNAc and the C2 position of GlcUA in the HS chain are sulfated to form highly complex HS side chains. Compared with heparin (Hep), HS has a more complex structure, manifested by more diverse sulfurization modes, lower IdoA content, and longer polysaccharide chains. The HS polysaccharide chain can be roughly divided into three parts: the NA region, which is the region without sulfation modification; In the NS region, the GlcNAc residues in the disaccharide units have undergone deacetylation and sulfation modifications; The NA/NS region is a mixed region of NA and NS, where many sulfation and isomerization modifications in HS occur. HS participates in various physiological and pathological processes such as growth, development, and disease occurrence through interactions with growth factors, cytokines, matrix proteins, etc.