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B6db references: 2071583

type Journal Article
authors Green, J. M.; Nichols, B. P.
title p-Aminobenzoate biosynthesis in Escherichia coli. Purification of aminodeoxychorismate lyase and cloning of pabC
journal J Biol Chem
sel selected
ui 2071583
year (1991)
volume 266
number 20
pages 12971-5
keywords 4-Aminobenzoic Acid/*metabolism
abstract p-Aminobenzoate, a component of the vitamin folate, is one of seven compounds derived from the aromatic precursor chorismate in Escherichia coli. Historically the gene products of pabA and pabB were assumed to be sufficient for de novo p-aminobenzoate biosynthesis. Recent studies, however, have shown that these proteins, as nonidentical subunits of a single enzyme, act on chorismate to form a diffusible intermediate, most likely 4-amino-4-deoxychorismate. This intermediate is then converted to p-aminodeoxychorismate lyase (Nichols, B. P., Seibold, A. S., and Doktor, S. Z. (1989) J. Biol. Chem. 264, 8597-8601). Here we describe partial characterization of the intermediate and the purification of aminodeoxychorismate lyase 4100-fold to near homogeneity. Further purification of this enzyme by high pressure liquid chromatography permitted isolation of a pure sample that yielded N-terminal sequence. A 64-fold redundant oligonucleotide probe was used to identify a lambda clone containing the gene encoding aminodeoxychorismate lyase. The aminodeoxychorismate lyase gene, designated pabC, was mapped to 25 min on the E. coli chromosome and lies on a 7.5-kilobase pair EcoRI fragment. A strain harboring a pACYC184 recombinant containing pabC overproduced aminodeoxychorismate lyase activity 77-fold.
last changed 2009/06/23 09:29

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