Linked Life Data

8422366

Source:http://linkedlifedata.com/resource/pubmed/id/8422366

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1993-2-23
pubmed:abstractText
The effects of cholera toxin, a secretory product of Vibrio cholerae, result from ADP-ribosylation of the stimulatory guanine nucleotide-binding (Gs) protein of the adenylyl cyclase system. Cholera toxin A subunit (CTA) also uses agmatine, a simple guanidino compound, several proteins unrelated to Gs, and CTA itself as alternative ADP-ribose acceptors. The effects of toxin occur in the jejunum presumably at body core temperature. With agmatine as a model substrate, the optimal temperature for CTA-catalyzed ADP-ribosylation was 25-30 degrees C, and that for CTA-catalyzed auto-ADP-ribosylation was 20-25 degrees C. Both activities were significantly less at 37 degrees C, reflecting lower initial velocities, not heat-inactivation of the toxin. All the transferase activities of CTA are enhanced by ADP-ribosylation factors (ARFs), approximately 20-kDa guanine nucleotide-binding proteins that are ubiquitous in mammalian cells. Phospholipids and a soluble brain ARF, in a GTP-dependent manner, activated toxin NAD:agmatine ADP-ribosyltransferase activity; their simultaneous effect was maximal at physiological temperatures (approximately 37 degrees C). At lower temperatures, the stimulation by ARF was much less. There were similar effects on other toxin-catalyzed reactions, notably, the ADP-ribosylation of Gs alpha and the hydrolysis of NAD. Thus, host factors, such as ARF and phospholipid, synergistically increase cholera toxin activity at 37 degrees C and may be important in toxin action in the mammalian gut.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
19
pubmed:volume
32
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
561-6
pubmed:dateRevised
2005-11-17
pubmed:meshHeading
pubmed:year
1993
pubmed:articleTitle
Effects of temperature on ADP-ribosylation factor stimulation of cholera toxin activity.
pubmed:affiliation
Laboratory of Cellular Metabolism, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892.
pubmed:publicationType
Journal Article