Yubin Hong, Byeol Kim, Jaehoon Jeong, Himani Bisht, Suho Park, Daewha Hong.The Journal of Physical Chemistry Letters 2022, 13 Reversible Supramolecular Noncovalent Self-Assembly Determines the Optical Properties and the Formation of Melanin-like Nanoparticles. Alexandra Mavridi-Printezi, Arianna Menichetti, Lucia Ferrazzano, Marco Montalti.Hydrophobic Melanin via Post-Synthetic Modification for Controlled Self-Assembly. Siwicka, Xinyi Gong, Navjit Paul, Karthikeyan Gnanasekaran, Christopher Forman, Omar K. Xuhao Zhou, Shengyi Su, Bram Vanthournout, Ziying Hu, Florencia A.Rational Assembly of Polymer–Metal Coordination Hierarchical Superstructures for Azathioprine-Responsive Electrodes in Biological Samples. Bhuvanenthiran Mutharani, Palraj Ranganathan, Jen-Ming Yang, Yen-Hsiang Chang, Fang-Chyou Chiu, Hsieh-Chih Tsai.First Evidence of Pheomelanin-UVA-Driven Synthesis of Pummerer’s Ketones by Peroxidase-Mediated Oxidative Coupling of Substituted Phenols. Sofia Gabellone, Eliana Capecchi, Lucrezia Anastasia Ortelli, Raffaele Saladino.Flexible Photothermal Materials with Controllable Accurate Healing and Reversible Adhesive Abilities. Li Yang, Luji Li, Junjie Lu, Baofeng Lin, Lihua Fu, Chuanhui Xu.This article is cited by 99 publications. We believe that this timely Perspective will introduce this class of biopolymer to the broader chemistry community, where we hope to stimulate new opportunities in novel, melanin-based poly-functional synthetic materials. We will emphasize efforts to elucidate biosynthetic pathways and structural characterization approaches that can be harnessed to interrogate specific structure–function relationships, including electron paramagnetic resonance (EPR) and solid-state nuclear magnetic resonance (ssNMR) spectroscopy. In this perspective, we will discuss the synthesis of melanin materials with a special focus beyond polydopamine. In the past decade, polydopamine, which has served as the conventional form of synthetic eumelanin, has dominated the literature on melanin-based materials, while the synthetic analogues of other melanins have received far less attention. Synthetic mimics have begun to play a broader role in unraveling structure and function relationships of natural melanins. Despite its long history of study, the exact chemical makeup of melanin remains unclear, and it moreover has an inherent diversity and complexity of chemical structure, likely including many functions and properties that remain to be identified. Generally, melanin is classified into five types-eumelanin, pheomelanin, neuromelanin, allomelanin, and pyomelanin-based on the various chemical precursors used in their biosynthesis. Its presence in nature from microorganisms to higher animals and plants is attributed to the many functions of melanin, including pigmentation, radical scavenging, radiation protection, and thermal regulation. Many pharmacologically active substances are able to inhibit or stimulate melanin biosynthesis, as evidenced by in vitro studies on cultured pigment cells.Melanin is ubiquitous in living organisms across different biological kingdoms of life, making it an important, natural biomaterial. Activity of the key melanogenic enzyme, tyrosinase, is also affected by pH and temperature. The article presents the intracellular signaling pathways: cAMP/PKA/CREB/MITF cascade, MAP kinases cascade, PLC/DAG/PKCβ cascade and NO/cGMP/PKG cascade, which are involved in the regulation of expression and activity of the melanogenesis-related proteins by ultraviolet radiation and endogenous agents (cytokines, hormones). Regulation of melanogenesis is achieved by physical and biochemical factors. Eumelanin is formed by polymerization of DHI and DHICA and their quinones. ![]() In the absence of thiol compounds DOPAquinone undergoes an intramolecular cyclization and oxidation to form DOPAchrome, which is then converted to 5,6-dihydroksyindole (DHI) or 5,6-dihydroxyindole-2-carboxylic acid (DHICA). The addition of cysteine or glutathione to DOPAquinone leads to the intermediates formation, followed by subsequent transformations and polymerization to the final product, pheomelanin. Melanogenesis is a multistep process and begins with the conversion of amino acid L-tyrosine to DOPAquinone. ![]() Biosynthesis of melanins takes place in melanosomes, which are specialized cytoplasmic organelles of melanocytes - dendritic cells located in the basal layer of the epidermis, uveal tract of the eye, hair follicles, as well as in the inner ear, central nervous system and heart. Melanins are natural pigments of skin, hair and eyes and can be classified into two main types: brown to black eumelanin and yellow to reddish-brown pheomelanin.
0 Comments
Leave a Reply. |