Control of lactate production by Selenomonas ruminantium

homotropic activation of lactate dehydrogenase by pyruvate

Research output: Contribution to journalArticle

32 Citations (Scopus)

Abstract

Selenomonas ruminantium produced one mole of D(-)-lactate per mole of glucose used at all dilution rates in ammonia-limited continuous culture. In contrast, lactate production varied according to the dilution rate when glucose was the limiting nutrient. At dilution rates of less than 0.2 h-1, acetate and propionate were the main fermentation products and lactate production was low. At dilution rates above 0.2 h-1, the pattern changed to one of high lactate production similar to that under ammonia limitation. Experiments with cell-free extracts of S. ruminantium showed that D(-)-lactate dehydrogenase had sigmoidal kinetics consistent with homotropic activation of the enzyme by its substrate, pyruvate. This feature allows S. ruminantium to amplify the effects of relatively small changes in the intracellular concentration of pyruvate to cause much larger changes in the rate of production of lactate. Some confirmation that this mechanism of control occurs under physiological conditions was obtained in glucose-limited culture, in which the sigmoidal increase in lactate production was accompanied by a linear increase in pyruvate excretion as the dilution rate increased.
Original languageEnglish
Pages (from-to)45-52
Number of pages8
JournalJournal of General Microbiology
Volume107
Issue number1
DOIs
Publication statusPublished - Jul 1978

Fingerprint

Selenomonas
Pyruvic Acid
L-Lactate Dehydrogenase
Lactic Acid
Ammonia
Glucose
Enzyme Activation
Propionates
Cell Extracts
Fermentation
Acetates
Food

Cite this

@article{f7e86fe0ae5e42f5b1654e603a41058d,
title = "Control of lactate production by Selenomonas ruminantium: homotropic activation of lactate dehydrogenase by pyruvate",
abstract = "Selenomonas ruminantium produced one mole of D(-)-lactate per mole of glucose used at all dilution rates in ammonia-limited continuous culture. In contrast, lactate production varied according to the dilution rate when glucose was the limiting nutrient. At dilution rates of less than 0.2 h-1, acetate and propionate were the main fermentation products and lactate production was low. At dilution rates above 0.2 h-1, the pattern changed to one of high lactate production similar to that under ammonia limitation. Experiments with cell-free extracts of S. ruminantium showed that D(-)-lactate dehydrogenase had sigmoidal kinetics consistent with homotropic activation of the enzyme by its substrate, pyruvate. This feature allows S. ruminantium to amplify the effects of relatively small changes in the intracellular concentration of pyruvate to cause much larger changes in the rate of production of lactate. Some confirmation that this mechanism of control occurs under physiological conditions was obtained in glucose-limited culture, in which the sigmoidal increase in lactate production was accompanied by a linear increase in pyruvate excretion as the dilution rate increased.",
author = "Wallace, {R. John}",
note = "Medline is the source for the MeSH terms of this document.",
year = "1978",
month = "7",
doi = "10.1099/00221287-107-1-45",
language = "English",
volume = "107",
pages = "45--52",
journal = "Journal of General Microbiology",
issn = "0022-1287",
publisher = "Society for General Microbiology",
number = "1",

}

TY - JOUR

T1 - Control of lactate production by Selenomonas ruminantium

T2 - homotropic activation of lactate dehydrogenase by pyruvate

AU - Wallace, R. John

N1 - Medline is the source for the MeSH terms of this document.

PY - 1978/7

Y1 - 1978/7

N2 - Selenomonas ruminantium produced one mole of D(-)-lactate per mole of glucose used at all dilution rates in ammonia-limited continuous culture. In contrast, lactate production varied according to the dilution rate when glucose was the limiting nutrient. At dilution rates of less than 0.2 h-1, acetate and propionate were the main fermentation products and lactate production was low. At dilution rates above 0.2 h-1, the pattern changed to one of high lactate production similar to that under ammonia limitation. Experiments with cell-free extracts of S. ruminantium showed that D(-)-lactate dehydrogenase had sigmoidal kinetics consistent with homotropic activation of the enzyme by its substrate, pyruvate. This feature allows S. ruminantium to amplify the effects of relatively small changes in the intracellular concentration of pyruvate to cause much larger changes in the rate of production of lactate. Some confirmation that this mechanism of control occurs under physiological conditions was obtained in glucose-limited culture, in which the sigmoidal increase in lactate production was accompanied by a linear increase in pyruvate excretion as the dilution rate increased.

AB - Selenomonas ruminantium produced one mole of D(-)-lactate per mole of glucose used at all dilution rates in ammonia-limited continuous culture. In contrast, lactate production varied according to the dilution rate when glucose was the limiting nutrient. At dilution rates of less than 0.2 h-1, acetate and propionate were the main fermentation products and lactate production was low. At dilution rates above 0.2 h-1, the pattern changed to one of high lactate production similar to that under ammonia limitation. Experiments with cell-free extracts of S. ruminantium showed that D(-)-lactate dehydrogenase had sigmoidal kinetics consistent with homotropic activation of the enzyme by its substrate, pyruvate. This feature allows S. ruminantium to amplify the effects of relatively small changes in the intracellular concentration of pyruvate to cause much larger changes in the rate of production of lactate. Some confirmation that this mechanism of control occurs under physiological conditions was obtained in glucose-limited culture, in which the sigmoidal increase in lactate production was accompanied by a linear increase in pyruvate excretion as the dilution rate increased.

UR - http://www.scopus.com/inward/record.url?scp=0017892033&partnerID=8YFLogxK

U2 - 10.1099/00221287-107-1-45

DO - 10.1099/00221287-107-1-45

M3 - Article

VL - 107

SP - 45

EP - 52

JO - Journal of General Microbiology

JF - Journal of General Microbiology

SN - 0022-1287

IS - 1

ER -