bookmark RF-Hydroxysite Identifies putative hydroxylysine and hydroxyproline residues in proteins. RF-Hydroxysite was tested with the jack-knife cross validation method and an independent test set. It is able to annotate potential hydroxylation sites within a protein with high confidence. The tool uses only the primary amino acid sequence as input to identify putative hydroxylation sites. It contains features such as cumulative hydrophobicity and position-specific entropy.