In Memoriam: Osamu Hayaishi (1920 – 2015).

Journal of Lipid Research Volume 57, 2016 517 Copyright © 2016 by the American Society for Biochemistry and Molecular Biology, Inc. Dr. Osamu Hayaishi, a world-renowned biochemist and oxygenase scientist, passed away on December 17, 2015, at the age of 95. He was the teacher of the authors of this tribute. In 1932, a short paper reported “ the presence of an oxydase of lipid or lipoxydase of soy seed ” ( 1 ). Later the “ lipoxidase ” was crystallized and its properties were described by Theorell et al. ( 2 ). Although lipoxidase was the fi rst example of “ oxygenase ” , its characterization as an oxygenase awaited the epoch-making work in 1955 by the groups of Mason and Hayaishi as will be described below. Osamu Hayaishi was born in Stockton, CA, in 1920 when his father studied and practiced medicine in the United States. In 1923, his family returned to Japan after visiting Germany for some time. He graduated from Osaka Imperial University School of Medicine in 1942, and then served in the navy as a medical offi cer until the end of the World War II. When he decided to become a basic researcher, the laboratory conditions were miserable. There were no chemicals or experimental animals, and the research facilities were almost useless. In several works ( 3 – 7 ) written by Hayaishi himself, he vividly and concretely described his life in Japan immediately after World War II. A famous biochemist at Osaka University, Yashiro Kotake, extensively studied tryptophan metabolism in mammals. His group ’ s approach was to feed animals with tryptophan and to extract and analyze the urinary metabolites. Their famous contribution was the discovery of kynurenine as a central metabolite, which was further transformed to kynurenic, xanthurenic, and anthranilic acids. Fortunately, Kotake donated several grams of tryptophan to Hayaishi, and this “ tryst with tryptophan ” ( 4 ) was the starting point of Hayaishi ’ s lifelong research and led him to the discovery of oxygenase.