There is no general preparation protocal: backteria != yeast != plant != animal

1. step in protein sample preparation

step in protein preparation towards 2d-page

1)- cell disruption (or collection of extracellular medium)

细胞破坏（或细胞外培养基的收集）

2)- protein extraction - removal of interfering substances

Concentrated protein solutions suffer from poor solubility. Three types of components aid solubilization, by interfering in
protein interactions.浓缩蛋白溶液的溶解性差。三种类型的成分通过干扰蛋白质相互作用来辅助溶解蛋白.

• chaotrope(reduce the hydrophobic effect by disruption H-bond in water) 破坏水中H键的降低疏水作用
• detergent(reduce hydrophobic interactions, preference to uncharged molecules. e.g. CHAPS)
• reducing agents (s-s bond breaking, e.g.DTT)

3)- protein solubilization and stabilization

remove of interfering compounds

2. reduce proteome complexity: tools

plasma proteomics: 75% proteins not interested

• clean up kits: to remove abundant proteins
• pre-fractionation:

1. cell fractionation (FACS,LCM)
2. organelle separation: differential centrifugation
3. Chromatographic separation or (enrichment of particular subfamilies of proteins: free-flow electrophoresis)