The invention provides therapeutic or diagnostic antibodies with modified N— or C-terminal sequences that are enriched with 
lysine or 
tyrosine residues. These 
lysine or tyfosine residues can be used to couple radioisotopes, cytotoxic agents, or detectable labels. The increased stoichiometric ratios of these agents in the 
antibody conjugates lead to improved therapeutic 
efficacy or enhanced detection sensitivity. Non-limiting examples of antibodies suitable for the present invention include anti-CD22, anti-
ErbB2, anti-VEGF, anti-EGFR, anti-VEGFR, anti-Her-3, anti-Her-4, anti-CEA, anti-CTLA-4, anti-CD4, anti-CD3, anti-CD20, anti-TNF-a, anti-CD11a, anti-Lewis Y 
antigen, anti-TrailR, anti-IL2R, anti-CD30, anti-CD146, anti-CD147, anti-alpha V 
integrin beta, anti-CD19, anti-GD2, anti-3H11, anti-EBV, anti-HIV, anti-HBV, anti-HCV, and other 
disease-specific antibodies.