Reductive metabolism of carbon tetrachloride by human cytochromes P-450 reconstituted in phospholipid vesicles: mass spectral identification of trichloromethyl radical bound to dioleoyl phosphatidylcholine

Details

• Personal Author:
  Bosterling B ; Trevor AJ ; Trudell JR
• Description:
  A reconstituted vesicle system with human cytochrome-P-450 was used in an extensive study of the reductive metabolism of carbon- tetrachloride (56235) (CCl4). This study demonstrated that the major reductive metabolite of carbon-tetrachloride by cytochrome-P- 450 was the trichloromethyl free radical and that this free radical was able to bind to double bonds of fatty acyl chains of the phospholipids in the membrane surrounding cytochrome-P-450. The structural identification of the reactive free radical metabolite and the product of its addition to phospholipids was accomplished by use of a reconstituted system of human cytochrome-P-450, NADPH- cytochrome-P-450-reductase, and cytochrome-b5 in phospholipid vesicles. The reconstituted vesicles contained a mixture of dioleoyl- phosphatidylcholine and egg phosphatidylethanolamine that served as both structural components and targets for trichloromethyl free radical binding. After incubation of these vesicles under a nitrogen atmosphere in the presence of NADPH with carbon-14 (C-14) labeled CCl4, the phospholipids were extracted and then separated by high performance liquid chromatography. The doleoyl- phosphatidylcholine fraction was transesterified and the resulting single C-14 labeled fatty acid methyl ester was purified by reverse phase chromatography. Desorption chemical ionization mass spectrometry with ammonia as reagent gas as well as desorption electron impact mass spectrometry permitted identification of the molecular structure as a mixture of 9 and 10 (trichloromethyl)stearate methyl esters. [Description provided by NIOSH]
• Subjects:
  Energy Metabolism Enzymes Hydrocarbons Occupational Health Safety Solvents
• Keywords:
  Chlorinated-hydrocarbons Enzyme-activity Grants-other In-vitro-studies Metabolic-study NIOSH-Grant NIOSH-Publication
• ISSN:
  0027-8424
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Journal Article
• Place as Subject:
  California ; OSHA Region 9
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Volume:
  79
• Issue:
  8
• NIOSHTIC Number:
  nn:00187033
• Citation:
  Proc Natl Acad Sci U.S.A. 1982 Apr; 79(8):2678-2682
• Contact Point Address:
  Anesthesia Stanford University Department of Anesthesia Stanford, Calif 94305
• CAS Registry Number:
  Carbon tetrachloride (CAS RN 56-23-5)
• Federal Fiscal Year:
  1982
• NORA Priority Area:
  Other Occupational Concerns ; Grants Other
• Performing Organization:
  Stanford University, Stanford, California
• Peer Reviewed:
  True
• Start Date:
  19800901
• Source Full Name:
  Proceedings of the National Academy of Sciences of the United States of America
• End Date:
  19901130
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:7b3cf4d3751f32925d564d2167f38abca8591c4554f97cbfeca4ea1a4f8d45e5cfd7ee6fcb7ef021bfbee1a1bab4f0dabbb16b026a5d513bc211fe4c81de3bbb
• Download URL:
  https://stacks.cdc.gov/view/cdc/205476/cdc_205476_DS1.pdf
• File Type:
  [PDF - 1.02 MB ]