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Title: Mutants of Escherichia coli deficient in the fermentative lactate dehydrogenase

Abstract

Mutants of Escherichia coli deficient in the fermentative NAD-linked lactate dehydrogenase (ldh) have been isolated. These mutants showed no growth defects under anaerobic conditions unless present together with a defect in pyruvate formate lyase (pfl). Double mutants (pfl ldh) were unable to grow anaerobically on glucose or other sugars even when supplemented with acetate, whereas pfl mutants can do so. The ldh mutation was found to map at 30.5 min on the E. coli chromosome. The ldh mutant FMJ39 showed no detectable lactate dehydrogenase activity and produced no lactic acid from glucose under anaerobic conditions as estimated by in vivo nuclear magnetic resonance measurements. We also found that in wild-type strains the fermentative lactate dehydrogenase was conjointly induced by anaerobic conditions and an acidic pH. Despite previous findings that phosphate concentrations affect the proportion of lactic acid produced during fermentation, we were unable to find any intrinsic effect of phosphate on lactate dehydrogenase activity, apart from the buffering effect of this ion.

Authors:
; ;  [1]
  1. Southern Illinois Univ., Carbondale (USA)
Publication Date:
OSTI Identifier:
7066980
DOE Contract Number:  
AC02-82ER12095
Resource Type:
Journal Article
Journal Name:
Journal of Bacteriology; (USA)
Additional Journal Information:
Journal Volume: 171:1; Journal ID: ISSN 0021-9193
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; ESCHERICHIA COLI; ENZYME ACTIVITY; LACTATE DEHYDROGENASE; ANAEROBIC CONDITIONS; BIOSYNTHESIS; FERMENTATION; LACTIC ACID; MUTANTS; PHOSPHATES; BACTERIA; BIOCONVERSION; CARBOXYLIC ACIDS; ENZYMES; HEMIACETAL DEHYDROGENASES; HYDROXY ACIDS; MICROORGANISMS; ORGANIC ACIDS; ORGANIC COMPOUNDS; OXIDOREDUCTASES; OXYGEN COMPOUNDS; PHOSPHORUS COMPOUNDS; SYNTHESIS; 550500* - Metabolism

Citation Formats

Mat-Jan, F, Alam, K Y, and Clark, D P. Mutants of Escherichia coli deficient in the fermentative lactate dehydrogenase. United States: N. p., 1989. Web.
Mat-Jan, F, Alam, K Y, & Clark, D P. Mutants of Escherichia coli deficient in the fermentative lactate dehydrogenase. United States.
Mat-Jan, F, Alam, K Y, and Clark, D P. 1989. "Mutants of Escherichia coli deficient in the fermentative lactate dehydrogenase". United States.
@article{osti_7066980,
title = {Mutants of Escherichia coli deficient in the fermentative lactate dehydrogenase},
author = {Mat-Jan, F and Alam, K Y and Clark, D P},
abstractNote = {Mutants of Escherichia coli deficient in the fermentative NAD-linked lactate dehydrogenase (ldh) have been isolated. These mutants showed no growth defects under anaerobic conditions unless present together with a defect in pyruvate formate lyase (pfl). Double mutants (pfl ldh) were unable to grow anaerobically on glucose or other sugars even when supplemented with acetate, whereas pfl mutants can do so. The ldh mutation was found to map at 30.5 min on the E. coli chromosome. The ldh mutant FMJ39 showed no detectable lactate dehydrogenase activity and produced no lactic acid from glucose under anaerobic conditions as estimated by in vivo nuclear magnetic resonance measurements. We also found that in wild-type strains the fermentative lactate dehydrogenase was conjointly induced by anaerobic conditions and an acidic pH. Despite previous findings that phosphate concentrations affect the proportion of lactic acid produced during fermentation, we were unable to find any intrinsic effect of phosphate on lactate dehydrogenase activity, apart from the buffering effect of this ion.},
doi = {},
url = {https://www.osti.gov/biblio/7066980}, journal = {Journal of Bacteriology; (USA)},
issn = {0021-9193},
number = ,
volume = 171:1,
place = {United States},
year = {1989},
month = {1}
}