So this question is part math, part biology, but I'm asking about the biology part here (or maybe the chemistry part). Basically I'm asking about my attempt to calculate the possible brightness per unit mass of GFP, and I'm asking if it makes sense. Here's what I've done: (I'm ignoring the quantum yield which should be 0.8):
GFP molar mass=27,000 amus (27 kDa)
1 mole weighs 27 kilograms
therefore 1 gram=(6.02*10^23)/27000=2*10^19 molecules of GFP
Assumption that I'm asking about; I'm assuming in this calculation that GFP releases light from one excited electron (roughly 2.5 electron volts). How many electrons are excited in GFP fluorescence?
(2*10^19)/(6*10^18), (the number of electrons in a Coulomb/amp)=3.3 amps
Brightness=2.5*3.3 =8.25 joules per gram
" The time constant of the fast, pH-dependent chemical process decreases with pH from 300 microseconds at pH 7 to 45 microseconds at pH 5..."
Given that's the case, that's roughly 3000 emissions (or 3333) per second (at 7 Ph), so
1 gram of GFP would have a maximum brightness of 24,750 watts, if there was enough UV light, or 25 watts for a milligram.
That sounds plausible, although high. Does that make sense, or what part of this calculation was wrong?