In this study the excited-state dynamics of protochlorophyllide a (PChlide), the substrate of the enzyme protochlorophyllide oxidoreductase, was examined by means of time-resolved absorption anisotropy and magic-angle measurements. The solvent polarity dependent anisotropy data provide strong evidence for the existence of an excited-state with charge-transfer character. A solvent dependency is also observed in the magic-angle kinetics. In a nonpolar environment wave packet oscillations are monitored while they are quenched in a polar solvent. These results show that the excited-state relaxations of PChlide are determined by the nature of the solvent environment. The implications of these findings are discussed with respect to the enzyme catalysed reaction. (C) 2010 Elsevier B. V. All rights reserved.