Dynamic and light scattering studies on melanin aggregation

L.Brancaleon, M.G. Bridelli, S. Losi, A. Vecli

Dept. of Physics, University of Parma

43100 Parma, Italy

Summary

The biosynthesis of melanins is a very complex in which non enzymatic steps follow the initial stages of transformation of the elemental precursors by tyrosinase.

Several aspects of this process can be mimicked by in vitro synthesis following standard procedures.

The in vitro synthesis kinetics, as studied by absorption and fluorescence spectroscopies and dynamic light scattering technique, put in evidence the superimposition of many effects, dependent mainly on the presence of the enzyme solution composition, and pH and suggests a possible anomalous effect in the enzymatic catalysis.

The evidence of the coexistence of different regimes of aggregation together with the presence of few dimensional critical values possibly related to internal structure and hydration of the final aggregates make it possible to formulate a tentative model that must be in any case confirmed by further measurements.