. Author manuscript; available in PMC: 2018 Jan 17.

Published in final edited form as: Chem Res Toxicol. 2016 Nov 16;30(1):162–176. doi: 10.1021/acs.chemrestox.6b00319

Table 4.

Enzymatic PAH Catechol Conjugation Relative to PAH o-Quinone Redox Cycling

recombinant enzyme⁻¹	specific activity (nmol min⁻¹ mg⁻¹) 10 μM B[a]P-7.8-dione^a
NQO1 + NADPH	1070^b
AKR7A2 + NADPH	1270^b
AKR1C1 + NADPH	64^b
COMT + S-adenosyl-L-methionine	55^c
SULT1A1 + phosphoadenosine phosphosulfate (PAPS)	0.8^c
UGT1A3 + UDP-glucuronic acid	>1.0^d

For catechol conjugation reactions catalyzed by COMT, SULT, or UGT, B[a]P-7,8-dione was reduced to the catechol with NADPH under anaerobic conditions.

Mean of six replicates with SD < 10%.

From Michaelis–Menten plots with homogeneous recombinant enzyme.

From commercial microsomes expressing recombinant UGT.