This application requests funding for the fifth in a series of International Symposia on Flavins and Flavoproteins, to be held in San Francisco, Calif. in March or April, 1975, with the principal investigator as Chairman and the co-investigator as a member of the Organizing Committee. Previous symposia in this series have been held in Amsterdam 1965, Nagoya, Japan 1962, Durham, N. C. 1969, Konstanz, Germany 1971. It is planned to invite 80 to 100 participants for 4 days of sessions, the majority of those invited being speakers, the rest discussants. It is planned to have extensive representation from fields allied to biochemistry, in which modern knowledge of flavins and flavoenzymes may catalyze research, such as x-ray crystallography, physical-organic chemistry, cell physiology, internal medicine, nutrition, etc. The symposium is an official activity of the International Union of Biochemistry, who have agreed to sponsorship, as have the U.S. Veterans Administration and the University of California. It is planned to publish the transactions of the symposium within a year of its termination, so as to assure maximum dissemination of information to emerge from this meeting. The application is intended primarily to fund the travel of young investigators who would be otherwise unable to attend.