Document Detail

Enzyme with dual lipoxygenase activities catalyzes leukotriene A4 synthesis from arachidonic acid.
MedLine Citation:
PMID:  6322165     Owner:  NLM     Status:  MEDLINE    
When arachidonic acid was incubated with homogenates of potato tubers, two isomers of 6-trans-leukotriene B4, epimeric at C-12, were formed in addition to the major product, (5S-hydroperoxy-6-trans-8,11,14-cis-icosatetraenoic acid (5-HPETE). To elucidate the mechanism of biosynthesis of the dihydroxy-acids, the lipoxygenase from the potato tubers was purified to apparent homogeneity by a combination of conventional chromatographic procedures and high-performance liquid chromatography equipped with a chromatofocusing column (Mono-P). The purified lipoxygenase acted on arachidonic acid and bishomo-gamma-linolenic acid to yield (5S)-hydroperoxy- and (8S)-hydroperoxyicosanoids, respectively. Furthermore, the purified enzyme converted 5-HPETE to leukotriene A4, with the presence of the epoxide intermediate being demonstrated by 18O2 experiments, methanol trapping, as well as further conversion to leukotriene B4 by the purified leukotriene A4 hydrolase. Several experiments, including those with lipoxygenase inhibitors, heat treatment, and competitive inhibition, indicated that both the 5-lipoxygenase and leukotriene A4 synthase activities resided in the same protein and that the formation of leukotriene A4 from 5-HPETE was catalyzed by the 8-lipoxygenase activity of the enzyme.
T Shimizu; O Rådmark; B Samuelsson
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Proceedings of the National Academy of Sciences of the United States of America     Volume:  81     ISSN:  0027-8424     ISO Abbreviation:  Proc. Natl. Acad. Sci. U.S.A.     Publication Date:  1984 Feb 
Date Detail:
Created Date:  1984-04-12     Completed Date:  1984-04-12     Revised Date:  2009-11-18    
Medline Journal Info:
Nlm Unique ID:  7505876     Medline TA:  Proc Natl Acad Sci U S A     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  689-93     Citation Subset:  IM    
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MeSH Terms
Arachidonic Acid
Arachidonic Acids / biosynthesis*,  metabolism*
Carbon Radioisotopes / diagnostic use
Leukotriene A4
Lipoxygenase / isolation & purification,  metabolism*
Plants / enzymology
Reg. No./Substance:
0/Arachidonic Acids; 0/Carbon Radioisotopes; 0/Leukotriene A4; 506-32-1/Arachidonic Acid; EC

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

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