para-aminobenzoate synthesis from chorismate occurs in two steps.
نویسندگان
چکیده
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.
منابع مشابه
Folate synthesis in plants: purification, kinetic properties, and inhibition of aminodeoxychorismate synthase.
pABA (p-aminobenzoate) is a precursor of folates and, besides esterification to glucose, has no other known metabolic fate in plants. It is synthesized in two steps from chorismate and glutamine, the first step being their conversion into glutamate and ADC (4-aminodeoxychorismate). In Escherichia coli, two proteins forming a heterodimeric complex are required for this reaction, but, in plants a...
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The mutant strain A erobacter aerogenes 62-1 AC, pab, accumulates a labile substance, desig nated Compound A which supports the growth of other pabmutants. Previous studies seemed to indicate that Compound A might be an intermediate in the conversion of chorismate to 4-aminobenzoate (Altendorf, Bacher, and Lingens, Z. Naturforsch. 24 b, 1602 [1969]). The present experi ments show that Compoun...
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It is not known how plants synthesize the p-aminobenzoate (PABA) moiety of folates. In Escherichia coli, PABA is made from chorismate in two steps. First, the PabA and PabB proteins interact to catalyze transfer of the amide nitrogen of glutamine to chorismate, forming 4-amino-4-deoxychorismate (ADC). The PabC protein then mediates elimination of pyruvate and aromatization to give PABA. Fungi, ...
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The metabolic fate of p-aminobenzoic acid (PABA) in Escherichia coli is its incorporation into the vitamin folic acid. PABA is derived from the aromatic branch point precursor chorismate in two steps. Aminodeoxychorismate (ADC) synthase converts chorismate and glutamine to ADC and glutamate and is composed of two subunits, PabA and PabB. ADC lyase removes pyruvate from ADC, aromatizes the ring,...
متن کاملEvolution of aminobenzoate synthases: nucleotide sequences of Salmonella typhimurium and Klebsiella aerogenes pabB.
p-Aminobenzoate synthase (PS) and anthranilate synthase (AS) are structurally related enzymes that catalyze similar reactions and produce similar products, para- and ortho-aminobenzoate (anthranilate). Each enzyme is composed of two non-identical subunits: a glutamine amidotransferase subunit (CoII) and a subunit that produces an aminobenzoate product (CoI). Nucleotide sequence comparisons of t...
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عنوان ژورنال:
- The Journal of biological chemistry
دوره 264 15 شماره
صفحات -
تاریخ انتشار 1989