MOLECULAR GENETIC BASIS OF THE N-ACETYLATION POLYMORPHISM IN C56BL/6J AND A/J MICE (C56BL 6J MICE).

NAT-1, NAT-2$\sp{\rm 99asn}$, and NAT-2$\sp{\rm 99ile}$ transiently expressed in COS-1 cells had different substrate specificities. All three enzymes acetylated 2-aminofluorene, but none acetylated sulfamethazine. p-Aminobenzoic acid was a preferred substrate for both NAT-2$\sp{\rm 99asn}$ and NAT-2$\sp{\rm 99ile}$, while isoniazid was a preferred substrate for NAT-1. Kinetic constants differed for NAT-2$\sp{\rm 99asn}$ and NAT-2$\sp{\rm 99ile}$. NAT-2$\sp{\rm 99ile}$ was less stable at 37$\sp\circ$C