Figure 2.

Significant derivatives of Hey include its thiolactone form (HTL), which reacts with Lys residues to form post-translational modifications. The Hcy-Lys isopeptide results from protein degradation. HTL, N-Hcy-protein, and N_ε-Hcy-Lys each have shown evidence of significant health impact. However, there is a lack of selective abiotic optical indicators dyes and probes that have targeted these analytes. Their physiological and structural relationships render them intriguing targets for multiple binding site probes.