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Production of Amino Acids by Fermentation
Published in Nduka Okafor, Benedict C. Okeke, Modern Industrial Microbiology and Biotechnology, 2017
Nduka Okafor, Benedict C. Okeke
In addition derivatives of amino acids are widely used in medicine as discussed below. Methyldopa (L-methy1-3, 4 dihydroxy-phenylalanine) is widely used as an anti- hypertensive with relatively few side effects. Dopa is used in treating Parkinson’s disease.
Effects of anti-wrinkle and skin-whitening fermented black ginseng on human subjects and underlying mechanism of action
Published in Journal of Toxicology and Environmental Health, Part A, 2020
Jin Ju Park, Junmin An, Jung Dae Lee, Hyang Yeon Kim, Jueng Eun Im, Eunyoung Lee, Jaehyoun Ha, Chang Hui Cho, Dong-Wan Seo, Kyu-Bong Kim
The skin is a protective outer covering extending throughout the human body which protects internal tissues and organs. Human skin is composed of three primary layers; the epidermis, dermis, and hypodermis. The epidermis, the outermost layer of the skin, functions by protecting the body and is predominantly composed of keratinocytes, melanocytes, Langerhans, and Merkel cells. Keratinocytes are the most abundant cells found in the epidermis and function as a barrier against the external environment (McGrath, Eady, and Pope 2004; Winkelmann and Breathnach 1973). Melanocytes produce the colored pigment of melanin. Melanin occurs in two forms in human skin: eumelanin and pheomelanin. Eumelanin is black and brown melanin and common throughout the body, while pheomelanin is a red or yellow melanin pigment (Wakamatsu and Ito 2002). Melanin is biosynthesized from tyrosine. Tyrosine is converted to DOPA (3,4-dihydroxy-L-phenylalanine), which is then oxidized to DOPA-quinone and subsequently converted to DOPA-chrome. Melanin is finally generated through several intermediates and a series of biochemical steps. Tyrosinase plays a key role in the melanin biosynthetic pathway by converting tyrosine to DOPA (Choi et al. 2001; D’Mello et al. 2016; Kong et al. 2000). The inhibition of tyrosinase leads to blockade of melanin production. The reaction of tyrosinase (activity or inhibition) with test material is used as a measure of the efficacy of the compound. Melanin, which is synthesized and matures in the melanosome, is transferred to keratinocytes where pigmentation occurs. Skin color is determined by melanin in the melanocytes. Melanocytes function predominantly by producing melanin pigment, which protects against and absorbs harmful ultraviolet (UV) radiation (D’Mello et al. 2016).