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Enzyme organization in the proline biosynthetic pathway of Escherichia coli

Journal Article:

Abstract

The conversion of glutamic acid to proline by an Escherichia coli extract was studied. The activity was dependent upon the presence of ATP and NADPH and was largely unaffected by the presence of NH/sub 3/ or imidazole. The first two pathway enzymes appear to exist as a complex which stabilizes a labile intermediate postulated as ..gamma..-glutamyl phosphate. Attempted synthesis of this compound was unsuccessful due to its spontaneous cyclization to 2-pyrrolidone 5-carboxylate. Dissociation of the enzyme complex upon dilution of the extract is presumed responsible for an experimentally observed dilution effect. E. coli pro/sub A//sup -/ and pro/sub B//sup -/ auxotroph extracts failed to complement one another in the biosynthesis of proline. This is attributed to the lack of a dynamic equilibrium between the complex and its constituent enzymes. In vivo studies with E. coli showed no evidence for metabolic channeling in the final reaction of proline synthesis, the reduction of ..delta../sup 1/-pyrroline 5-carboxylate.
Authors:
Publication Date:
Jan 01, 1974
Product Type:
Journal Article
Reference Number:
EDB-79-027579
Resource Relation:
Journal Name: Biochim. Biophys. Acta; (Netherlands); Journal Volume: 354
Subject:
59 BASIC BIOLOGICAL SCIENCES; ESCHERICHIA COLI; PROLINE; BIOSYNTHESIS; ATP; BIOCHEMISTRY; CARBOXYLIC ACIDS; ENZYMES; GLUTAMIC ACID; NUCLEOTIDES; AMINES; AMINO ACIDS; AZOLES; BACTERIA; CHEMISTRY; HETEROCYCLIC ACIDS; HETEROCYCLIC COMPOUNDS; MICROORGANISMS; ORGANIC ACIDS; ORGANIC COMPOUNDS; ORGANIC NITROGEN COMPOUNDS; PYRROLES; PYRROLIDINES; SYNTHESIS; 550200* - Biochemistry
OSTI ID:
6505114
Research Organizations:
Univ. of California, Berkeley
Country of Origin:
Netherlands
Language:
English
Other Identifying Numbers:
Journal ID: CODEN: BBACA
Submitting Site:
TIC
Size:
Pages: 75-87
Announcement Date:

Journal Article:

Citation Formats

Gamper, H, and Moses, V. Enzyme organization in the proline biosynthetic pathway of Escherichia coli. Netherlands: N. p., 1974. Web.
Gamper, H, & Moses, V. Enzyme organization in the proline biosynthetic pathway of Escherichia coli. Netherlands.
Gamper, H, and Moses, V. 1974. "Enzyme organization in the proline biosynthetic pathway of Escherichia coli." Netherlands.
@misc{etde_6505114,
title = {Enzyme organization in the proline biosynthetic pathway of Escherichia coli}
author = {Gamper, H, and Moses, V}
abstractNote = {The conversion of glutamic acid to proline by an Escherichia coli extract was studied. The activity was dependent upon the presence of ATP and NADPH and was largely unaffected by the presence of NH/sub 3/ or imidazole. The first two pathway enzymes appear to exist as a complex which stabilizes a labile intermediate postulated as ..gamma..-glutamyl phosphate. Attempted synthesis of this compound was unsuccessful due to its spontaneous cyclization to 2-pyrrolidone 5-carboxylate. Dissociation of the enzyme complex upon dilution of the extract is presumed responsible for an experimentally observed dilution effect. E. coli pro/sub A//sup -/ and pro/sub B//sup -/ auxotroph extracts failed to complement one another in the biosynthesis of proline. This is attributed to the lack of a dynamic equilibrium between the complex and its constituent enzymes. In vivo studies with E. coli showed no evidence for metabolic channeling in the final reaction of proline synthesis, the reduction of ..delta../sup 1/-pyrroline 5-carboxylate.}
journal = {Biochim. Biophys. Acta; (Netherlands)}
volume = {354}
journal type = {AC}
place = {Netherlands}
year = {1974}
month = {Jan}
}