Polymer complexes, melanin formation

In the present paper we describe the catalytic mechanisms of synthetic polymer-Cu complexes a catalytic interaction between the metal ions which attached to a polymer chain at high concentration and an environmental effect of polymer surrounding Cu ions. In the latter half, the catalytic behavior is compared with the specific one of tyrosinase enzyme in the melanin-formation reaction which is a multi-step reaction. To the following polymers Cu ions are combined. 

Nicolaus [10] and Mason [11] have described our current knowledge of the structure of melanic pigments, the most preponderant pigments of human hair. Two theories are still considered for the structure of melanin, and both consider structures involved in Raper s scheme (Figure 4-26) [54, 55], as intermediates in the formation of all melanic pigments. Nicolaus [56] has proposed that melanin is a complex random polymer (Figure 4-27), formed from several species of the Raper scheme. This is the favored scheme at this time. 

Tables. Formation of melanin catalyzed by polymer-copper (II) complexes...

Binding studies combined with ESR spectroscopy have revealed the mechanism of the interaction of metal ions with melanins which indicates the formation of a chelate complex between di- and trivalent diamagnetic metal ions and o-semiquinone radical centers on the pigment polymer (85, 124). This interaction often results in an increase of total free radical concentration. Furthermore, the binding capacity varies for melanins of different origins with the number of reactive sites (230). 

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