We previously reported evidence that humans metabolize benzene via two enzymes,
including a hitherto unrecognized high-affinity enzyme that was responsible for an estimated
73% of total urinary metabolites [sum of phenol (PH), hydroquinone (HQ), catechol (CA), E,
E-muconic acid (MA), and S-phenylmercapturic acid (SPMA)] in nonsmoking females
exposed to benzene at sub-saturating (ppb) air concentrations. Here, we used the same
Michaelis–Menten-like kinetic models to individually analyze urinary levels of PH, HQ, CA …