The Osamu Hayaishi Lecture

An exciting new era in the study of biological oxidations emerged from works reported in 1955 by Howard S. Mason and his colleagues on mushroom phenolase and by Osamu Hayaishi and his coworkers on pseudomonad pyrocatechase. These investigators utilized the heavy oxygen isotope 18O to examine metabolic transformations and showed that oxygen atoms from molecular oxygen (O2) can be incorporated into organic substrates.

This was a surprising finding because until that time O2 was only thought to serve as a terminal electron acceptor in biological oxidations. Enzymes catalyzing oxygen insertion reactions became referred to as oxygenases. There are monooxygenases and dioxygenases that incorporate either one or two atoms of molecular oxygen, respectively.

While first discovered in lower organisms, oxygenases were soon found in various mammalian tissues by Dr. Hayaishi and many other investigators. Oxygenases are now known to be involved in the metabolism of sugars, amino acids, steroids, fatty acids and aromatic drugs and carcinogens. The molecular and catalytic properties of oxygenases have been thoroughly investigated with special reference to their prosthetic iron and copper and their flavin and pterin cofactors. Dr. Hayaishi and his colleagues have made major contributions to our understanding of oxygenases, especially those functioning in the metabolism of tryptophan, lysine and histidine and in the biosynthesis of bioactive eicosanoids. Most recently, Dr. Hayaishi has focused his studies on elucidating the role of prostaglandins in sleep.

Dr. Hayaishi is well-known not only as a distinguished researcher but also as a stimulating and influential educator. More than 100 university professors and institute directors have received training in his laboratory. His famous "lunch seminar" served as an occasion for teaching his students how to read and discuss scientific articles critically and how to develop research projects so as make significant contributions to biology and medicine.

Dr. Hayaishi has contributed importantly to the IUBMB. He has given two plenary lectures at IUB and IUBMB Congresses, one in New York in 1964 and another in New Delhi in 1994. He was elected to the IUB Council in 1969, and served as the President of the IUB from 1973-1976. His autobiographical "Memoirs of a Biochemist" appeared in IUBMB Life, 58, 242-245 (2006).

The Osamu Hayaishi Lecture was inaugurated in 1982 at the 12th IUB Congress in Perth, Australia and is sponsored by funds provided by Suntory Limited.