title: para-aminobenzoate synthesis from chorismate occurs in two steps.
abstract: Escherichia coli p-aminobenzoate synthase is composed of two nonidentical subunits encoded by pabA and pabB and has been assumed to be the sole enzyme responsible for p-aminobenzoate biosynthesis from chorismate and glutamine. Plasmids were constructed that overproduce the p-aminobenzoate synthase subunits 250-500-fold. Partial purification of the subunits revealed that they form a diffusible intermediate that is subsequently converted to p-aminobenzoate by a second enzyme (Mr = 49,000) temporarily designated enzyme X.
authors.affiliation: Department of Biological Sciences, University of Illinois, Chicago, 60680.
authors.forename: B P
authors.initials: BP
authors.lastname: Nichols
authors.forename: A M
authors.initials: AM
authors.lastname: Seibold
authors.forename: S Z
authors.initials: SZ
authors.lastname: Doktor
mesh_terms: D010129:4-Aminobenzoic Acid / Q000378:metabolism; D001483:Base Sequence; D002827:Chorismic Acid / Q000378:metabolism*; D003509:Cyclohexanecarboxylic Acids / Q000378:metabolism*; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics; D008969:Molecular Sequence Data; D010957:Plasmids; D000637:Transaminases / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D003509:Cyclohexanecarboxylic Acids; C022309:PABA synthase; D000637:Transaminases; D002827:Chorismic Acid; D010129:4-Aminobenzoic Acid