D-Luciferin (Free acid)

Synthetic. StayBrite™ D-Luciferin is a luminescent substrate for firefly luciferase (Km ~2 μM). Note: Unlike the Potassium (Cat. No.7903) or Sodium (Cat. No. 7902) salts, Luciferin free acid is not soluble in water. It requires the addition of dilute NaOH or KOH to aid the free acid to go into solution.