Document Detail


Ascorbic acid transport and accumulation in human neutrophils.
MedLine Citation:
PMID:  2681206     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The transport, accumulation, and distribution of ascorbic acid were investigated in isolated human neutrophils utilizing a new ascorbic acid assay, which combined the techniques of high performance liquid chromatography and coulometric electrochemical detection. Freshly isolated human neutrophils contained 1.0-1.4 mM ascorbic acid, which was localized greater than or equal to 94% to the cytosol, was not protein bound, and was present only as ascorbic acid and not as dehydroascorbic acid. Upon addition of ascorbic acid to the extracellular medium in physiologic amounts, ascorbic acid was accumulated in neutrophils in millimolar concentrations. Accumulation was mediated by a high affinity and a low affinity transporter; both transporters were responsible for maintenance of concentration gradients as large as 50-fold. The high affinity transporter had an apparent Km of 2-5 microns by Lineweaver-Burk and Eadie-Hofstee analyses, and the low affinity transporter had an apparent Km of 6-7 mM by similar analyses. Each transporter was saturable and temperature dependent. In normal human blood the high affinity transporter should be saturated, whereas the low affinity transporter should be in its linear phase of uptake.
Authors:
P Washko; D Rotrosen; M Levine
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Publication Detail:
Type:  In Vitro; Journal Article    
Journal Detail:
Title:  The Journal of biological chemistry     Volume:  264     ISSN:  0021-9258     ISO Abbreviation:  J. Biol. Chem.     Publication Date:  1989 Nov 
Date Detail:
Created Date:  1989-12-15     Completed Date:  1989-12-15     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  2985121R     Medline TA:  J Biol Chem     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  18996-9002     Citation Subset:  IM    
Affiliation:
Laboratory of Cell Biology and Genetics, National Institute of Diabetes, Digestive, and Kidney Diseases, Bethesda, Maryland 20892.
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MeSH Terms
Descriptor/Qualifier:
Ascorbic Acid / blood*
Biological Transport
Carbon Radioisotopes
Cell Fractionation
Humans
Kinetics
Neutrophils / metabolism*
Radioisotope Dilution Technique
Subcellular Fractions
Chemical
Reg. No./Substance:
0/Carbon Radioisotopes; 50-81-7/Ascorbic Acid

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


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