| Biosynthesis of the morphine alkaloids. | |
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MedLine Citation:
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PMID: 5332945 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Tracer experiments, supported throughout by the analogous chemical transformations, have firmly established the biosynthetic sequence tyrosine -->norlaudanosoline --> reticuline --> salutaridine --> salutaridinol-I -->thebaine --> codeine --> morphine in Papaver somniferum. In general, the farther a precursor lies along this sequence, the more efficient its conversion to morphine in the intact plant. Several intermediates remain to be discovered, such as those lying between tyrosine and norlaudanosoline and between thebaine and codeine. Proof that morphine is made only by the reticuline-salutaridine route is still lacking and would require a careful comparison of the rate of morphine synthesis with the turnover rates for the various intermediates. More importantly, detailed knowledge of the mechanism of each biochemical step can come only with isolation of the enzyme system involved. The chemical oxidation of (-)-reticuline, to give salutaridine, can only be accomplished in very low (0.02 percent) yield (15, 26), whereas, even with whole plants, the biological incorporation of reticuline into the morphine alkaloids can reach 8 percent (13). One would like to know just how an enzyme system directs the oxidative cyclization of reticuline in the desired sense. Kleinschmidt and Mothes and Fairbairn and Wassel (27) have shown that the latex isolated from opium poppies is capable of transforming tyrosine into morphine. Perhaps further work with opium latex will provide the key to the remaining problems of morphine biosynthesis. |
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Authors:
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G W Kirby |
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Publication Detail:
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Type: Journal Article; Review |
Journal Detail:
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Title: Science (New York, N.Y.) Volume: 155 ISSN: 0036-8075 ISO Abbreviation: Science Publication Date: 1967 Jan |
Date Detail:
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Created Date: 1967-02-09 Completed Date: 1967-02-09 Revised Date: 2011-12-02 |
Medline Journal Info:
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Nlm Unique ID: 0404511 Medline TA: Science Country: UNITED STATES |
Other Details:
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Languages: eng Pagination: 170-3 Citation Subset: IM |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Morphine
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biosynthesis* Plants, Medicinal / metabolism* Tyrosine / metabolism |
| Chemical | |
Reg. No./Substance:
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55520-40-6/Tyrosine; 57-27-2/Morphine |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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