Table 1.

Shifts in absorption band maxima in cm⁻¹ relative to those in solution resulting from binding of naphthols in the pKSI active site and the fraction of the neutral species observed when bound. Errors indicate one standard deviation.

Ligand	Protein	Neutral shift	Anionic shift	Fraction neutral
Equilenin	WT	−280 ±17	446 ± 28	0.31 ± 0.02
Equilenin	D40N	−180 ± 14	730 ± 56	0.456 ± 0.005
6-bromo-2-naphthol	D40N	−475 ± 7	190 ± 28	0.32 ± 0.02
2,6-hydroxynaphthalene	D40N	−405 ± 63	1230 ± 212	0.71 ± 0.01
6-cyano-2-naphthol	D40N	−1480 ± 280	275 ± 7	0.08 ± 0.03
6-methoxy-2-naphthol	D40N	−390 ± 14	235 ± 7	0.54 ± 0.03