Participates in the detoxification of a plethora of hydrazine and arylamine drugs. Isoniazid, 2-aminofluorene and anisidine are preferred substrates for NAT-1. No activity with p-aminobenzoic acid (PABA) nor SMZ. acetyl-CoA + an arylamine = an N-acetylarylamine + CoA Belongs to the arylamine N-acetyltransferase family.