The e volution of chlorophyll containing photoactive structures

Some facts illustrating the evolution of protein-chlorophyll complexes are briefly presented and discussed. considering especially the lipoproteinprotochlorophyllide found in etiolated leaves, it is shown that the lipoprotein plays an essential role in the photoactivity, a feature which opposes the generally accepted view. The concept of photoenzyme is thereafter introduced, and a qualitative, general model of photoactivity of living structures is presented which gives a theoretical basis to the concept. Finally it is shown, at the hand of some examples, that the photoenzyme concept may clarify the interpretation of the relationships between photoactivity and enzymatic activity, and of the evolution of these relationships in the living world.