Compositions, and methods of using such compositions, having the following Formula (I) or salt, ester, or hydrate thereof, wherein R1 is Asp-Glu peotide, tert-butyloxycarbonyl, methoxyphenylacetyl, bromomethoxyphenylaceityl, fluoromethoxyphenylacetyl, (methylmethoxyphenyl)acetyl, or iodomethoxyphenylacetyl; R2 is valine with or without protecting groups), aspartale (with or without protecting groups), 1-Butyl, hydrogen, aniline, aromatic molecules, tert-butyloxycarbonyl, or fluorenyl-methoxy-carbonyl; and R3 is p-nitroaniline, 7-amino-4-methylcoumarin, fluoroethylamine, 1-amino-4-fluoromethyl-cyclohexane, 1-amino-4-fluoroethyl-cyclohexane, aniline, p-fluoroaniline, p-fluoromethylaniline, p-fluorobenzylamine, p-fluoromethylbenzylamine, 4-aminopiperidine, 4-amino-1-fluoroethylpiperidine, or 4-amino-1-fluoropropylpiperidine.