Crossover experiment (chemistry) or phosphine. The mechanisms of enzyme-catalyzed reactions can also be studied using crossover experiments. Examples of the application of this technique in biochemistry include the study of reactions catalyzed by nucleoside diphosphohexose-4,6-dehydratases, the aconitase-catalyzed elimination of water from citrate, and various reactions catalyzed by coenzyme B-dependent enzymes, among others. Unlike isotope labeling studies in organic and organometallic chemistry, which typically use deuterium when an isotope of hydrogen is desired, biochemical crossover experiments frequently employ tritium. This is due to the fact that tritium is radioactive and can be tracked using the autoradiographs of gels in gel electrophoresis. Isotope labeling experiments
Tritium evident was the decrease in tritium in the deep western boundary current by a factor of 10 from the Labrador Sea to the Tropics, which is indicative of loss to ocean interior due to turbulent mixing and recirculation. In a 1998 study, tritium concentrations in surface seawater and atmospheric water vapor (10 meters above the surface) were sampled at the following locations: the Sulu Sea, the Fremantle Bay, the Bay of Bengal, the Penang Bay, and the Strait of Malacca. Results indicated that the tritium concentration in surface seawater was highest at the Fremantle Bay (approximately 0.40 Bq/liter), which could