This award will enable Prof. Leslie R. Berger of the University of Hawaii at Manoa to collaborate with Professor Yoshihiro Taniguchi of Ritsumeikan University in Kyoto, Japan over a period of one year. They will study the activity of malate dehydrogenases, MDH, to determine how barophilic, barotolerant and barophobic enzymes with the same catalytic activity and structure are different. MDH enzyme samples will be prepared in the U.S. investigator's laboratory, and subsequently studied in Kyoto. Fluorometry will be used to determine the total protein in each enzyme. The immediate activity, and changes in activity of each enzyme system will then be measured as functions of time, pressure, and rate of pressure change. The effects of pressure on dissociation and reassociation will also be studied. The U.S. investigator has long been involved in the characterization of hydrostatic pressure as an environmental parameter in biological systems. The Japanese collaborators have similar long experience in studying the effects of pressure on chemical systems. The complemen- tary interests and equipment of these workers will greatly increase the productivity of this research. These studies should have important implications in the understanding of the adaptation in molecular structure which has taken place in deep-sea organisms.