these cells are shown to be thioguanine resistant , to be unable to incorporate exogenously added hypoxanthine into purine nucleotides , to complement our other adenine-specific purine auxotrophs , ade-h and ade-i but not to complement a cell isolated by virtue of thioguanine resistance , and to lack the activity of hgprt .
C0034140
purine
C0039902
thioguanine