Document Detail

Production of ornithine by intact human erythrocytes.
MedLine Citation:
PMID:  7081429     Owner:  NLM     Status:  MEDLINE    
Although the conversion of arginine to ornithine in humans is largely an hepatic process, erythrocytes also have this enzymatic capacity. We have shown that intact human erythrocytes readily produce ornithine from arginine and release product ornithine to the incubation medium. The rate of ornithine formation from arginine was 0.22 cells-1, and 85% of the ornithine is recovered extracellularly. Moreover, we have shown that ornithine and urea are the unique and stoichiometric products of arginine metabolism in the intact erythrocyte. The rate of ornithine production by intact red blood cells was a saturable function of arginine concentration in the medium; the derived Km for arginine for this conversion was 0.16 mM, a value striking for its close approximation to physiological arginine concentration in human plasma. We propose that the production and delivery of ornithine by intact red blood cells may supply peripheral tissues such as bone and muscle with an important precursor for proline and polyamines.
J A Williams; J M Phang
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  The American journal of physiology     Volume:  242     ISSN:  0002-9513     ISO Abbreviation:  Am. J. Physiol.     Publication Date:  1982 May 
Date Detail:
Created Date:  1982-07-08     Completed Date:  1982-07-08     Revised Date:  2004-11-17    
Medline Journal Info:
Nlm Unique ID:  0370511     Medline TA:  Am J Physiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  C393-7     Citation Subset:  IM    
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MeSH Terms
Arginine / metabolism
Erythrocytes / metabolism*
Ornithine / biosynthesis*
Urea / biosynthesis
Reg. No./Substance:
57-13-6/Urea; 7006-33-9/Ornithine; 74-79-3/Arginine

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

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