The data returned by the Target Information API call includes:

(All targets must have an associated UniProt URI to have data returned from the API.  This means that presently only protein entities are found by this call.)

From ConceptWiki: the preferred label of the target.

From DrugBank:
The subcellular location;
The number of amino acid residues in the sequence;
The theoretical pI of the sequence.

From UniProt: 

Textual annotations giving a general description of the function(s) of the target;

Alternative names;

A (classifiedWith) list of URI's that correspond to: 

  • UniProt keywords (a list of controlled vocabulary which summarizes the content of theUniProt entry) 
  • GO terms that have been selected for the UniProt entry
  • the IntAct website link for the interactions with the target

An annotation concerning the existence of a protein. There are 5 types of evidence that supports the existence of a protein:

  • Evidence at protein level, clear experimental evidence for the existence of the protein
  • Evidence at transcript level, existence of a protein has not been strictly proven but that expression data indicate the existence of a transcript
  • Inferred from homology, existence of a protein is probable because clear orthologs exist in closely related species
  • Predicted, the evidence at protein, transcript, or homology levels is not available
  • Uncertain, the existence of the protein is uncertain

The organism source of the target, given with the NCBI taxonomic identifier, e.g.;

(interactsWith) list of the interaction information relevant to binary protein-protein interactions as curated by UniProt for IntAct;

A (seeAlso) list of cross references to Protein Database (PDB), a 3D structure database;

From Chembl:
The target component URI's. The target can be composed of either a single protein or a group of interacting proteins. Each case will have a representative Chembl target component URI (CHEMBL_TC_identifier);
The target type.  The target type categorization is used to describe the molecular (DNA and protein) and non-molecular (organisms, tissues, cell lines, and subcellular fractions) each target component.  Within the protein targets, there are 7 "target types":
    • Single protein targets i.e.
    • 6 types of multi-protein targets
      • Protein family. Groups of closely related proteins
      • Protein complex. Defined groups of proteins that form a multi-subunit complex
      • Protein complex group. Poorly defined protein complexes where the subunit composition is unclear
      • Selectivity group. Pairs of protein for which the selectivity has been assessed.
      • Protein-Protein interaction. The target is the disruption of the protein-protein interaction
      • Chimeric protein. Fusion of two different proteins, either a synthetic construct or a naturally occurring fusion protein