Measurement of styrene-oxide cysteine adducts in hemoglobin by selective catalytic reduction.
Ting-D; Smith-MT; Doane-Setzer-P; Woodlee-J; Rappaport-SM
Adv Exp Med Biol 1991 Jan; 283:837-841
Alkylating agents, either direct-acting or generated in vivo, form an important class of environmental mutagens and carcinogens. These agents are characterized by their ability to bind covalently to nucleophilic sites in proteins and DNA. Due to the long life time of red blood cells and the stability of protein adducts, Ehrenberg and coworkers first (Calle man 1978; Osterman-Golkar 1976) proposed the use of hemoglobin (Hb) as a dosimeter for alkylation in vivo. Since then, several methods have been devised to detect hemoglobin adducts (Bryant 1987; Calleman 1978; Farmer 1980; Neumann 1984). Here, we report an alternative method that is sensitive, specific and relatively simple. It is based on the well known desulfurization by Raney nickel (Ra-Ni) (Pettit 1962; Pizey 1974), in which the carbon-sulphur bond formed by the alkylating agent and cysteine is selectively cleaved and at least one new carbon-hydrogen bond is formed. Pachecka et al. (Pachecka 1979) demonstrated that when styrene-7,8-oxide-glutathione adducts were refluxed with Ra-Ni in ethanol, 1-phenylethanol (1-PE) and 2-phenylethanol (2-PE) were produced. This reaction between cysteine-bound styrene oxide and Ra-Ni is shown in Figure 1. We utilized this reaction to determine the amount of cysteine-bound styrene-7,8-oxide (SO) which reacted with Hb in vitro and in vivo.
Styrenes; Epoxy-compounds; Animals; Metabolism; Toxic-effects; Erythrocytes; Drugs; Humans; Men; Oxidation-reduction-reactions; Laboratory-animals; Mutagens; Carcinogens; In-vitro-study; In-vivo-study; Alkylating-agents; Chemical-binding; Proteins; Deoxyribonucleic-acids; DNA-adducts; Dosimetry; Red-blood-cells
S. M. Rappaport, Dept. of Biomedical and Environmental Health Sciences, School of Public Health, University of California, Berkeley, CA 94720
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Advances in Experimental Medicine and Biology
University of North Carolina, Chapel Hill