| Autor: |
Friedberg SJ, Weintraub ST, Singer MR, Greene RC |
| Jazyk: |
angličtina |
| Zdroj: |
The Journal of biological chemistry [J Biol Chem] 1983 Jan 10; Vol. 258 (1), pp. 136-42. |
| Abstrakt: |
We have previously presented evidence for the formation of 1-O-alkyl dihydroxyacetone-P from acyl dihydroxyacetone-P via the initial formation of an intermediate 1-O-acyl endiol of acyl dihydroxyacetone-P. This reaction involves a stereospecific exchange of the pro-R hydrogen of the acyl dihydroxyacetone-P moiety without change in configuration. The fatty acid is replaced by a long chain fatty alcohol which retains the oxygen of the primary carbinol. In the absence of fatty alcohol, water substitutes and the product is dihydroxyacetone-P which has also exchanged the pro-R hydrogen with a hydrogen from the medium. An absolute requirement of the proposed mechanism is that the loss of the fatty acid must proceed via an unusual cleavage of the dihydroxyacetone-P C-1 to oxygen bond instead of the usual cleavage at the fatty acid acyl to oxygen bond. In the present investigation, we have synthesized hexadecanoyl dihydroxyacetone-P containing oxygen-18 exclusively at the dihydroxyacetone-P C-1 oxygen. Using this substrate, we have shown that cleavage of hexadecanoyl dihydroxyacetone-P at the C-1 to oxygen bond is linked to O-alkyl dihydroxyacetone-P synthesis. Inhibition of O-alkyl lipid synthesis by means of magnesium or NADPH inhibited the unusual cleavage. At the same time, we have shown that there was hydrolysis of acyl dihydroxyacetone-P which proceeded by the usual mechanism and which was not related to synthesis of O-alkyl dihydroxyacetone-P. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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