negatively regulates negative regulation of protein modification process post-translational protein modification biological regulation regulation of post-translational protein modification negative regulation of post-translational protein modification inhibition of PTM down-regulation of post-translational amino acid modification biological_process down-regulation of post-translational modification downregulation of post-translational modification down-regulation of posttranslational amino acid modification down-regulation of post-translational protein modification 2013-02-05T10:02:57Z negative regulation of PTM negative regulation of posttranslational protein modification downregulation of post-translational amino acid modification downregulation of posttranslational amino acid modification down-regulation of posttranslational modification Any process that stops, prevents or reduces the frequency, rate or extent of post-translational protein modification. down-regulation of posttranslational protein modification inhibition of post-translational modification down regulation of PTM negative regulation of post-translational modification inhibition of post-translational protein modification negative regulation of posttranslational modification downregulation of posttranslational protein modification down-regulation of PTM downregulation of PTM down regulation of post-translational amino acid modification down regulation of post-translational modification GO:1901874 negative regulation of post-translational amino acid modification inhibition of post-translational amino acid modification downregulation of post-translational protein modification negative regulation of posttranslational amino acid modification inhibition of posttranslational protein modification down regulation of posttranslational protein modification inhibition of posttranslational modification down regulation of posttranslational modification down regulation of posttranslational amino acid modification inhibition of posttranslational amino acid modification downregulation of posttranslational modification down regulation of post-translational protein modification yaf