| Amino acid | 
        Negative    control 
          (µM) | 
        Free-GHTHase 
          (µM) | 
        PEG-GHTHase 
          (µM) | 
       
      
        | Aspartic    acid | 
        181.36 | 
        177.6 | 
        147.04 | 
       
      
        | Threonine | 
        85.40 | 
        68.96 | 
        75.12 | 
       
      
        | Serine | 
        146.17 | 
        290.32 | 
        716.4 | 
       
      
        | Glutamic    acid | 
        647.17 | 
        936.96 | 
        743.48 | 
       
      
        | Glycine | 
        108.68 | 
        398.48 | 
        155.96 | 
       
      
        | Alanine | 
        123.08 | 
        156.08 | 
        140.0 | 
       
      
        | Valine | 
        132.53 | 
        132.96 | 
        104.8 | 
       
      
        | Methionine | 
        330.68 | 
        25.9 | 
        47.6 | 
       
      
        | Cysteine  | 
        267.0 | 
        57.9 | 
        89.0 | 
       
      
        | Isoleucine | 
        129.06 | 
        165.8 | 
        149.6 | 
       
      
        | Leucine | 
        266.86 | 
        261.36 | 
        865.04 | 
       
      
        | Tyrosine | 
        500.0 | 
        559.04 | 
        508.88 | 
       
      
        | Phenylalanine | 
        45.58 | 
        84.8 | 
        107.76 | 
       
      
        | Histidine | 
        120.38 | 
        110.0 | 
        138.4 | 
       
      
        | Lysine | 
        212.48 | 
        105.2 | 
        122.88 | 
       
      
        | Arginine | 
        266.03 | 
        116.08 | 
        125.0 | 
       
      
        | Proline | 
        378.935 | 
        348.5687 | 
        369.9019 | 
       
      |