ethylene oxide (EtO)


OTHER NAMES:
oxirane
epoxyethane
epoxyethane
dimethylene oxide
oxacyclopropane


ABBREVIATIONS:
EO
EtO


DESCRIPTION: Ethylene oxide, also called oxirane, is the organic compound with the formula C2H4O. It is a cyclic ether. This means that it is composed of two alkyl groups attached to an oxygen atom in a cyclic shape (circular). This colorless flammable gas with a faintly sweet odor is the simplest epoxide, a three-membered ring consisting of two carbon and one oxygen atom. Because of its special molecular structure, ethylene oxide easily participates in the addition reaction, opening its cycle, and thus easily polymerizes. Ethylene oxide is isomeric with acetaldehyde.

Ethylene oxide inhibits growth of microorganisms (disinfectant properties) and when present in high concentrations, can completely destroy them. Strong alkylating properties make ethylene oxide a universal poison for protoplasm: it causes clotting of proteins, deactivation of enzymes and other biologically important components of a living organism.
Ethylene oxide acts more strongly against bacteria, especially gram-positive bacteria, than against yeast and fungi. The disinfectant effect of ethylene oxide is similar to that of sterilization by heat, but because of limited penetration, it affects only the surface. The Sterility Assurance Level, after a certain specified exposure to ethylene oxide is 10−6, meaning that the chance of finding a single bacterium is below 1 per million.

Ethylene oxide is an alkylating agent; it has irritating, sensitizing and narcotic effects. Chronic exposure to ethylene oxide also induces mutagenic effects. The International Agency for Research on Cancer classifies ethylene oxide into group 1, meaning it is a proven carcinogen. A 2003 study of 7,576 women exposed while at work in commercial sterilization facilities in the U.S. suggests ethylene oxide is associated with breast cancer incidence. A 2004 follow up study analyzing 18,235 men and women workers exposed to ethylene oxide from 1987 to 1998 concluded "There was little evidence of any excess cancer mortality for the cohort as a whole, with the exception of bone cancer based on small numbers. Positive exposure-response trends for lymphoid tumors were found for males only. Reasons for the sex specificity of this effect are not known. There was also some evidence of a positive exposure-response for breast cancer mortality.

CAS number (75-21-8)
PubChem (6354)
ChemSpider (6114)
EC number (200-849-9)
KEGG (D03474)
MeSH (Ethylene+Oxide)
ChEBI (CHEBI:27561)

DNA DAMAGES:
1,N6-etheno-A (1εA)
N1-OH-ethyl A (1heA)
1,N6-etheno-A in (1εA) dsDNA
1,N6-etheno-A (1εA) in ssDNA


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NAME STRUCTURE PROTEINS DNA DAMAGE EFFECT(S) PATHWAY(S) RELATED
1,N6-etheno-A (1εA) AlkA
Fpg (MutM)
ANPG (MPG)
AlkB
ALKBH2
A→T transversion
mutagenesis
point mutation
transversion
base excision repair (BER)
direct reversal (DR)
N1-OH-ethyl A (1heA) ANPG (MPG) mutagenesis base excision repair (BER)
1,N6-etheno-A in (1εA) dsDNA AlkA
Fpg (MutM)
ANPG (MPG)
AlkB
mutagenesis
point mutation
substitution
transition
transversion
base excision repair (BER)
direct reversal (DR)
1,N6-etheno-A (1εA) in ssDNA ALKBH2 mutagenesis
point mutation
transition
transversion
direct reversal (DR)

References:

  • Steenland K, Whelan E, Deddens J, Stayner L, Ward E (2003). "Ethylene oxide and breast cancer incidence in a cohort study of 7576 women (United States)". Cancer Causes Control 14 (6): 531–9. doi:10.1023/A:1024891529592

    , , : [PUBMED]

Last modification date: Oct. 5, 2011