Observation of ultrafast Q-band fluorescence in horse heart cytochrome c in reduced and oxidized forms

摘要

The dynamics of fluorescence from horse heart cytochrome c is investigated in reduced (ferrous) and oxidized (ferric) forms by a streak camera and an up-conversion technique under B-band excitation at 415 nm. In the reduced form, we found the Q-band emission at 550 and 600 nm originated from the S_1 state in a short time range. A very broad continuum observed from 440 to 660nm had only shown a slow component and was assigned to impurity. In the reduced form, the lifetime of S_1 was determined to be 120 fs by using the up-conversion technique. In the oxidized form, the S_1 lifetime was estimated to be 21 fs. These values are consistent with the values estimated from the quantum yield in order of their magnitude.