Sequencing of peptides via collision induced dissociation in conjunction with tandem mass analyses revealed the extent of deuterium incorporation at each amino acid amide site. The results confirmed predictions from models produced by energy minimization calculations performed by Dr. Ho on sites of hydrogen bonding between the adducted group and the protein. Information on the rate of contaminant degradation and product formation is needed to assess the risk to populations in the vicinity of a contaminated groundwater zone, whereas assessment of subsurface biomass is necessary for evaluating strategies designed to increase subsurface biomass and, thus, to an increase in the degradation rates of contaminants. Field and Barofsky have submitted a proposal to the EPA to investigate the occurrence and behavior of perfluorinated surfactants in municipal wastewater treatment systems. Perfluorooctane sulfonate, which persists in the environment, has been detected at part per billion levels in samples obtained from human blood banks in the United States, Japan, Europe and China as well as in tissues of animals from around the world.
Animal studies indicate that perfluorooctane sulfonate has toxicological properties.
Because large quantities of surfactants are disposed of through municipal wastewater treatment, elucidating the mass flow and changing composition of surfactants as they pass through wastewater treatment facilities will be an important step toward understanding the risk these compounds pose to human health and the environment. The entire protein structure was subjected to energy minimization to relieve strain in the starting model, and an ethylglutathionyl-group was constructed with the amino acids in their extended conformations off the sulfur of the protein's Cys32. This model of the modified thioredoxin places the ethylglutathione chain on a broad surface formed by two loop structures in the protein. It remains to demonstrate a correlation between this prediction and experiment.