Figure 1.

Formation of a transient blue complex by interaction of amino acid, Fz, and Fe(II). Reaction mixtures (1 ml) initially contained 20 mM Hepes buffer (pH 7.6), 160 μM Fz, and 80 mM amino acid, peptide, or N-acetyl amino acid. Spectral changes were initiated and monitored as described in Experimental Procedures. The symbols * and # identify initial and 10-min spectra, respectively.