| Phenomena           | 
        Procedures | 
       
      
        | Aggregation | 
        SDS-PAGE, SEC-HPLC.    light scattering   | 
       
      
        | Deamidation,    Oxidation | 
        Peptide map, HPLC,    IEF, MS   | 
       
      
        | Proteolytic Cleavage | 
        Peptide map,    SDS-PAGE, HPLC, IEF, MS   | 
       
      
        | Amino Acid    Substitutions | 
        AAA, Peptide map, MS,    protein sequence, CE   | 
       
      
        | Translation Mutations | 
        Peptide map, HPLC,    IEF, MS, CE   | 
       
      
        | Host Cell Proteins | 
        SDS-PAGE, Western    blot, ELISA   | 
       
      
        | Media Components | 
        SDS-PAGE, Western    blot, HPLC, ELISA   | 
       
      
        | Nucleic Acids | 
        DNA hybridization,    UV, Protein binding   | 
       
      
        | Affinity Antibodies | 
        SDS-PAGE, Western    blot, ELISA   | 
       
      
        | Proteases/Nucleases | 
        HPLC, Western blot,    ELISA   | 
       
      
        | Leachates/Extractables | 
        HPLC, MS, GC,    gravimetric analysis   | 
       
      
        | Process Residuals | 
        Karl Fisher moisture,    GC, ion chromatography   | 
       
      |