Location of the Aspartase Gene (aspA) on the linkage map of Escherichia coli K12.

The aspartase (L-asparatate ammonia-lyase, EC. 4.3.I.I) structural gene, aspA, was mapped by two-factor and three-factor transductional crosses using phage PI. Cotransduction frequencies between aspA and other markers were: ampA (69%); frdA (48 TO 67%) mel (35%); purA (17%); fdp (I-6%). The sequence of markers within the corresponding segment (91 to 95 min) of the Escherichia coli linkage map was shown to be mel-aspA-ampA-frdA-purA-fdp.