ALP N-acyl transferase (Lnt), is an essential membrane-bound enzyme in gram-negative bacteria, which catalyzes the N-acylation of apolipoproteins, the final step in lipoprotein maturation. This is a reverse amidase (i.e. condensation) reaction. This subgroup belongs to a larger nitrilase superfamily comprised of nitrile- or amide-hydrolyzing enzymes and amide-condensing enzymes, which depend on a Glu-Lys-Cys catalytic triad. This superfamily has been classified in the literature based on global and structure based sequence analysis into thirteen different enzyme classes (referred to as 1-13), this subgroup corresponds to class 9.