Chapter 1
Melanin Chemistry
Abstract The history and the current status of melanin chemistry are introduced
briefly. It is known now that melanin, a pigment found in animals, consists of two
types of oligomeric unit: eumelanin (black to brown) and pheomelanin (yellow to
reddish brown). The color of the skin, the hair, and the eyes is mainly determined by
the ratio of eumelanin/pheomelanin production as well as the total amount of melanin.
Among various reaction steps involved in the biosynthesis of melanin, there are two
branched reactions that directly affect the composition of melanin: (i) reaction of
dopachrome and (ii) reaction of dopaquinone. We introduce our approach to gain an
understanding of these reactions from atomic nuclei and electrons world.
Keywords Computational materials design (CMD
® ) · Melanin · Eumelanin ·
Pheomelanin · Melanocyte · Tyrosinase · Raper-Mason pathway
1.1 Overview
1.1.1 Significance of Fundamental Studies
Exploring microscopic behaviors of biochemical reactions is one of the challenges
in science. Living organisms have controlled chemical reactions by various proteins,
which had been naturally selected through evolution. Chemistry of biomolecules
including amino acids and proteins is one of the keys to understanding the
mechanisms of biochemical reactions.
Due to involvement of complex internal motions of biomolecules, mechanistic
studies have frequently encountered difficulties in describing the reactions. Furthermore, modeling of biochemical reactions often requires environmental factors that are
usually less significant in organic chemistry. For instance, hydrogen bonding, proton
exchange with water molecules, and catalytic interactions with co-existing metal ions
may participate in the reaction as necessary processes. Moreover, biochemical reactions usually appear in multi-step and multi-branch cascades, conferring diversity
and flexibility to the biochemical systems.
The above-mentioned complexity might contribute in part to realization of the
various functions of organisms. It is one of the goals of several fields, such as tissue
© The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2021
R. Kishida et al., Melanin Chemistry Explored by Quantum Mechanics,
https://doi.org/10.1007/978-981-16-1315-9_1
1
Melanin Chemistry
Abstract The history and the current status of melanin chemistry are introduced
briefly. It is known now that melanin, a pigment found in animals, consists of two
types of oligomeric unit: eumelanin (black to brown) and pheomelanin (yellow to
reddish brown). The color of the skin, the hair, and the eyes is mainly determined by
the ratio of eumelanin/pheomelanin production as well as the total amount of melanin.
Among various reaction steps involved in the biosynthesis of melanin, there are two
branched reactions that directly affect the composition of melanin: (i) reaction of
dopachrome and (ii) reaction of dopaquinone. We introduce our approach to gain an
understanding of these reactions from atomic nuclei and electrons world.
Keywords Computational materials design (CMD
® ) · Melanin · Eumelanin ·
Pheomelanin · Melanocyte · Tyrosinase · Raper-Mason pathway
1.1 Overview
1.1.1 Significance of Fundamental Studies
Exploring microscopic behaviors of biochemical reactions is one of the challenges
in science. Living organisms have controlled chemical reactions by various proteins,
which had been naturally selected through evolution. Chemistry of biomolecules
including amino acids and proteins is one of the keys to understanding the
mechanisms of biochemical reactions.
Due to involvement of complex internal motions of biomolecules, mechanistic
studies have frequently encountered difficulties in describing the reactions. Furthermore, modeling of biochemical reactions often requires environmental factors that are
usually less significant in organic chemistry. For instance, hydrogen bonding, proton
exchange with water molecules, and catalytic interactions with co-existing metal ions
may participate in the reaction as necessary processes. Moreover, biochemical reactions usually appear in multi-step and multi-branch cascades, conferring diversity
and flexibility to the biochemical systems.
The above-mentioned complexity might contribute in part to realization of the
various functions of organisms. It is one of the goals of several fields, such as tissue
© The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2021
R. Kishida et al., Melanin Chemistry Explored by Quantum Mechanics,
https://doi.org/10.1007/978-981-16-1315-9_1
1