For NAD(P)H , excite at 340 nm. Emission is at 460 nm in water.

NAD(P)+ is not fluorescent.

You can also measure the conversion of NAD(P)+ to NAD(P)H by the increase in absorbance at 340 nm. Or, you can measure the conversion of NAD(P)H to NAD(P)+ by the decrease in absorbance at 340 nm.

Both the fluorescence and absorbance signals can be monitored continuously.

Hello Povilas, the excitation wavelength for NAD(P)H is 340 nm. There is a great paper from Alexa von Ketteler (2012) describing fluorescent properties of NADH.

Article Fluorescence Properties of Carba Nicotinamide Adenine Dinucl...

I am not sure if there is a way to obtain reliable fluorescent signal from NAD(P). Normally, a fluorescent analog is used in this case (with modified adenine moiety).

Article Dynamic and static quenching of 1,N6-ethenoadenine fluoresce...

For NAD(P)H , excite at 340 nm. Emission is at 460 nm in water.

NAD(P)+ is not fluorescent.

You can also measure the conversion of NAD(P)+ to NAD(P)H by the increase in absorbance at 340 nm. Or, you can measure the conversion of NAD(P)H to NAD(P)+ by the decrease in absorbance at 340 nm.

Both the fluorescence and absorbance signals can be monitored continuously.

In general, I found the Spectra Database hosted at the University of Arizona pretty usefull.

http://spectra.arizona.edu/

There you can look up absorption maxima of many fluorophores.