BTI1, an azoreductase with pH-dependent substrate specificity.

The group II azoreductase BTI1 utilizes NADPH to directly cleave azo bonds in water-soluble azo dyes, including quenchers of fluorescence. Unexpectedly, optimal reduction was dye specific, ranging from a pH of <5.5 for Janus green B, to pH 6.

Synthesis and properties of phosphonic acid containing cyanine and squaraine dyes for use as fluorescent labels.

Cyanine and squaraine dyes that contain one or two phosphonate groups attached directly to the aromatic residues of the dyes were synthesized. Absorption and fluorescence properties of the dyes were determined. Succinimidyl active esters were prepared from the dyes and were used to label proteins and oligonucleotides.