Human serum albumin (HSA) contains a single tryptophan residue at posi
tion 214. The emission properties of tryptophan 214 from recombinant a
lbumins, namely, normal HSA, FDH-HSA and a methionine 218 HSA were exa
mined. In all cases, the excited state lifetimes mere best described b
y a two component model consisting mainly of a Lorentzian distribution
. The centers of these distributions were 5.60 ns for HSA, 4.23 ns for
FDH-HSA, and 6.08 ns for Met-218 HSA. The global rotational correlati
on times of the three HSAs were near 41 ns while the amplitude and rat
e of the local motion varied. These changes in the lifetimes and mobil
ities suggest perturbation in the local protein environment near trypt
ophan 214 as a consequence of the amino acid substitutions. (C) 1997 F
ederation of European Biochemical Societies.