PKAD database contains experimentally measured pKa values for >1500 ionizable residues in wild
type as well as mutant proteins. The wild type proteins, for which structures are available in
the protein databank, considered in the database and PDB ID is given. For some of the mutant
proteins, structure files are not available. In these cases, PDB IDs of wild type proteins are
provided. Relative solvent accessible surface area (%SASA), provided in the database, will guide
user to identify surface exposed and buried residues in a given protein.