Distribution and HPLC study of chromium-51 binding sites in Chinese hamster ovary cells.
J Toxicol Environ Health 1987 Jan; 21(3):375-386
The distribution and nature of chromium (7440473) binding sites were studied in-vitro. Chinese-hamster ovary cell cultures were incubated with chromium-51 (Cr-51) labeled sodium-chromate (7775113) at a concentration of 60 nanomolar for 2 or 24 hours. The cells were washed, homogenized, and separated into fractions by centrifugation. The Cr-51 activity and protein content of each fraction were measured. The supernatant from the centrifuged homogenate was dialyzed and examined by anion exchange and ion pair high performance liquid chromatography. At least 75 percent of the Cr-51 activity was found in the nonsedimentable cytosolic fraction. A small, significant amount of radiolabel was found in the nuclear fraction. Dialysis through a membrane with a 12000 dalton cutoff caused a loss of 90 percent of the Cr-51 and 60 percent of the protein after 18 hours. Chromatographic analyses indicated the presence of at least three different molecular species interacting with chromate or its reduced derivative trivalent chromium (16065831). Two species were identified as glutathione and nucleoside diphosphates and triphosphates. The third species appeared to be a protein or peptide, eluting under the same conditions as metallothionein. The glutathione accounted for 50 percent of the observed Cr-51 activity and the nucleotides 30 percent. The remaining activity was due to the unknown species. The authors note that most of the chromate taken up by nucleated cells is not protein bound but resides in small, easily dialyzable molecules.
NIOSH-Publication; NIOSH-Grant; Chromium-compounds; In-vitro-studies; Mammalian-cells; Radioisotopes; Chemical-binding; Chemical-analysis; Molecular-structure; Physiological-chemistry; Subcellular-structure; Chromatographic-analysis
Pharmacology University of Kansas 39Th St at Rainbow Blvd Kansas City, Kans 66103
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Journal of Toxicology and Environmental Health
University of Kansas Col Hlth Sci & Hosp, Kansas City, Kansas