The preparation of solid-supported peptide boronic acids derived from 4-borono-L-phenylalanine and their affinity for alizarin

A library of solid-supported pentapeptide diboronic acids, a 'lysine series' and an 'arginine series', has been efficiently prepared using N-Fmoc-4-pinacolatoborono-L-phenylalanine and standard solid phase peptide synthesis methods. A technique for measuring the affinity of the chromophoric diol, alizarin, to the solid-supported peptide boronic acids has been developed. Considerable variation in alizarin binding strengths, both within and between arginine and lysine series was observed, with association constants in the range 200-1100 M-1 being recorded. The selective binding characteristics of these boronic acid-peptide hybrids suggest their potential use in carbohydrate sensors and cell-specific diagnostics and therapeutics.