The present invention provides modified cupredoxin derived peptides with pharmacologic activity that have improved pharmacokinetic properties, and methods to use them to treat mammals suffering from various conditions related to the pharmacologic activities. Modifications of the cupredoxin derived peptides include amino acid sequence variants and structural derivations that increase the plasma half-life of the peptide, increase the specific activity of the pharmacologic activity, decrease immunogenicity, and decrease the biotransformation of the peptides. The modified cupredoxin derived peptides can be used in methods to treat mammals for cancer, conditions related to inappropriate angiogenesis, viral and bacterial infections, and specifically HIV and malaria, conditions related to ephrin signaling, and to deliver cargo compounds, including diagnostic compounds, to cancer cells.