Picosecond dynamics of iron proteins

Abstract

The excitation of hemoproteins [cytochromes, porphyrins] containing either Fe2+ or Fe3+ with a picosecond light pulse resulted in the bleaching and recovery of the Fe absorbance bands within 6 ps. A new absorbance band also was observed whose formation and decay rate of less than 6 ps suggests that it is probably due to S1 .fwdarw. Sn absorbance. The Soret band relaxation time is deduced to be .apprx. 0.5 ps; the free base hemoprotein does not show any of the above fast-decay characteristics. There is a strong influence of the metal on the energy dissipation process.