O-linked High mannose Glycoprotein N-linked Complex Hybrid Versican Serglycin Soluble Secorin Proteoglycan Cartilage Transmembrane Syndecan Selectin Lectin Galectin C-reactive protein
重點整理 Glycoprotein O-linked:attach to hydroxyl groups * Usually N-acetylgalactosamine * 常有分支 * Functions:1. 增加彈性 2. 增加水溶性
N-linked:attach to the amide nitrogens * Have Core structure: By two N-acetylglucosamine and a branched mannose triad. * Functions:1. 改變蛋白質的物理和化學性質 2. 穩定蛋白質構型 3. 幫助蛋白質折疊 Sialic acid:被修飾在N-linked 的最末端,會隨 著時間脫落,而被辨識
Proteoglycans 大多為glycosaminoglycans (GAG) 在動物細胞膜、或細菌外殼 包含 soluble proteins:Versican, Serglycin, Secorin, Cartilage transmembrane proteins:Syndecan
Functions: 1. 與其他蛋白質結合:成為ECM中的Blue、與 生長因子作用 2. 調控細胞生長的過程:抑制細胞增殖、刺 激生長因子 3. 關節的緩衝:ex. Cartilage
Sugar Code and Lectins Sugar code:由 sugar 構成的訊號碼 Lectin:辨認sugar,或和sugar結合的蛋白質 ex. Selectin, Galectin, C-reactive protein (CRP)
習題 Q:What are the differences between proteoglycans and glycoproteins A:glycoprotein= protein (major)+glycan (minor) ex: Antifreeze Glycoproteins proteoglycan= core protein (minor)+GAGs (major) ex: heparin