Document Detail


Uptake of L-tryptophan by erythrocytes infected with malaria parasites (Plasmodium falciparum).
MedLine Citation:
PMID:  6338923     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The initial rates of uptake of L-tryptophan into normal human red blood cells and into cells infected by the malarial parasite Plasmodium falciparum in vitro, were investigated. We find that transport in non-infected cells, which is mediated by the specific saturable T system and the apparently non-saturable L system (Rosenberg, Young and Ellory (1980) Biochim. Biophys. Acta 598, 375-384) is considerably enhanced by blood preservation and culture conditions. This increase is mostly due to an increase in the maximal velocity of the saturable component and of the rate constant of the linear component. Uptake is further enhanced in non-infected cells by factors released from infected cells into the culture medium and, even more so, in infected cells at the advanced stage of intraerythrocytic parasite development. At these stages the susceptibility of the transport system to the non-specific inhibitor phloretin and to the competitive inhibitor phenylalanine, is virtually lost. The effect of the parasite on L-tryptophan uptake by the host cell membrane is exerted only on the maximal velocity of the T system, which is carrying most of the substrate under physiological conditions. The possible implications of these findings to the life of the intraerythrocytic parasite are briefly discussed.
Authors:
H Ginsburg; M Krugliak
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Biochimica et biophysica acta     Volume:  729     ISSN:  0006-3002     ISO Abbreviation:  Biochim. Biophys. Acta     Publication Date:  1983 Mar 
Date Detail:
Created Date:  1983-05-05     Completed Date:  1983-05-05     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0217513     Medline TA:  Biochim Biophys Acta     Country:  NETHERLANDS    
Other Details:
Languages:  eng     Pagination:  97-103     Citation Subset:  IM    
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MeSH Terms
Descriptor/Qualifier:
Biological Transport / drug effects
Chloroquine / pharmacology
Erythrocytes / drug effects,  metabolism*
Humans
Kinetics
Malaria / blood
Phenylalanine / pharmacology
Phloretin / pharmacology
Plasmodium falciparum / physiology*
Reference Values
Tryptophan / blood*
Chemical
Reg. No./Substance:
54-05-7/Chloroquine; 60-82-2/Phloretin; 63-91-2/Phenylalanine; 73-22-3/Tryptophan

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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