Calculation of the spectroscopic correction factor.

Abbreviations: MUNANA, 2′-(4-methylumbelliferyl)-α-D-N-acetylneuraminic acid; 4-MU, 4-methylumbelliferone; RFU, relative fluorescence units.aFluorescence of MUNANA alone in enzyme buffer at 1.95–2000 µM concentrations (shown in column 1).bFluorescence of 4-MU alone in enzyme buffer at 19 µM concentration. Mean (± SD) 4-MU fluorescence in enzyme buffer was 10222±90 RFU.cFluorescence of 4-MU in enzyme buffer at 19 µM concentration in the presence of 1.95–2000 µM MUNANA concentrations (shown in column 1).dValues (in RFU) of MUNANA fluorescence (column 2) subtracted from the values (in RFU) obtained in the mixture of 4-MU and MUNANA (column 4).eCorrection factor calculated as the ratio of 4-MU fluorescence (in RFU) in the mixture with MUNANA substrate (column 5) and 4-MU fluorescence (in RFU) alone (mean value from column 3).