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The systematic name of this enzyme class is benzene,NADH:oxygen oxidoreductase (1,2-hydroxylating). Other names in common use include benzene hydroxylase , and benzene dioxygenase . Biological role
The catechol dioxygenases, some of the most well-studied dioxygenase enzymes, use dioxygen to cleave a carbon-carbon bond of an aromatic catechol ring system. [4] Catechol dioxygenases are further classified as being “extradiol” or “intradiol,” and this distinction is based on mechanistic differences in the reactions (figures 1 & 2).
When exposure to toluene occurs there is usually simultaneous exposure to several other chemicals. [4] Often toluene exposure occurs in conjunction with benzene and since they are to some degree metabolised by the same enzymes, the relative concentrations will determine their rate of elimination. [4]
Aromatic-ring-hydroxylating dioxygenases (ARHD) incorporate two atoms of dioxygen (O 2) into their substrates in the dihydroxylation reaction.The product is (substituted) cis-1,2-dihydroxycyclohexadiene, which is subsequently converted to (substituted) benzene glycol by a cis-diol dehydrogenase.
Benzene 1,2-dioxygenase; The substrate specificity of these enzymes is low. Enantiomeric purities in excess of 90% are routine but varies with substrate. For instance, 1,4-substituted benzenes often render diols of lower enantiomeric purity. However, accessing the "unnatural" enantiomer of product is often difficult without tailored enzymes. (1)
According to the Centers for Disease Control and Prevention, acute benzene poisoning can cause symptoms such as drowsiness, dizziness, rapid or irregular heartbeat, headaches and even death at ...
The short term exposure limit for airborne benzene is 5 ppm for 15 minutes. [90] These legal limits were based on studies demonstrating compelling evidence of health risk to workers exposed to benzene. The risk from exposure to 1 ppm for a working lifetime has been estimated as 5 excess leukemia deaths per 1,000 employees exposed.
Cases of apparent carbon monoxide poisoning are raising concern about the "invisible killer" this holiday travel season. On Christmas Day, a family of four from Massachusetts was found dead inside ...