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Table 2 Effects of naphthoquinone 1 on the activity of mammalian NATs and their colorimetric detection

From: Differences between murine arylamine N-acetyltransferase type 1 and human arylamine N-acetyltransferase type 2 defined by substrate specificity and inhibitor binding

Enzyme (HUMAN) NAT1*4 (MOUSE) NAT2*1 (MESAU) NAT2*1 (MOUSE) NAT2_F125S (MOUSE) NAT2_R127G (MOUSE) NAT2_R127L (MOUSE) NAT1*1 (HUMAN) NAT2*4
Primary sequence identity versus (HUMAN)NAT1*4 100 82 81 82 82 82 74 71
Active site residues 125 F F F S F F Y S
127 R R R R G L G S
129 Y Y L Y Y Y Y S
IC50 with naphthoquinone 1 (μ M) 5.3a 1.3a,b 89.0c 68.7 51.7a 102.5a 129.7 >100
λ max of naphthoquinone 1 (nm) 585a,b 625a,b 525c 498 498a 498a 498b 498a
  1. IC50 values were calculated using decreasing concentrations of naphthoquinone 1. NAT activity was measured following the hydrolysis rate of AcCoA (400 μM) in the presence of 4ABA for (HUMAN)NAT1*4, (MOUSE)NAT2*1 and (MESAU)NAT2*1; 5AS for (MOUSE)NAT2 mutants and (MOUSE)NAT1*1; and 2-aminofluorene for (HUMAN)NAT2*4. aadapted from [25]badapted from [24]cadapted from [26]. Residues which are different from the corresponding residues in (HUMAN)NAT1*4 are labeled in bold.