Practice question

Colorimetric ELISA uses HRP, ALP and beta galactosidase to produce colored products, but sensitivity limited. Chemiluminescence enhances detection using enzymes or proteins generating light in presence of substrate. Luciferase catalyzes luciferin oxidation producing photons detectable by luminometer, vastly amplified compared to absorbance. GFP is fluorescent not chemiluminescent, ALP can also produce chemiluminescence with appropriate dioxetane substrates but luciferase is archetypal bioluminescent tag increasing signal to noise ratio. Fusion of luciferase to antibody improves limit of detection for low abundance antigens.