Stereochemistry of the acyl dihydroxyacetone phosphate acyl exchange reaction.

Autor: SJ Friedberg, N Satsangi, ST Weintraub
Jazyk: angličtina
Rok vydání: 1991
Předmět:
Zdroj: Journal of Lipid Research, Vol 32, Iss 2, Pp 259-266 (1991)
Druh dokumentu: article
ISSN: 0022-2275
DOI: 10.1016/S0022-2275(20)42087-5
Popis: The fatty acid of acyl dihydroxyacetone phosphate can be exchanged enzymatically for another fatty acid. It has been shown that this reaction proceeds by cleavage of the oxygen bound to C-1 of the dihydroxyacetone phosphate (DHAP) moiety rather than by the more common cleavage at the acyl to oxygen bond. In the present study, the stereochemistry of this reaction was defined further; using deuterated substrates and fast atom bombardment-mass spectrometry, it was shown that the fatty acid exchange involves the stereospecific labilization of the pro-R hydrogen at C-1 of the DHAP moiety of acyl DHAP. The mechanism of ether bond formation, in which acyl DHAP is converted to O-alkyl DHAP, also proceeds via labilization of the pro-R hydrogen and cleavage of the fatty acid at the C-1 to oxygen bond. In addition, other workers have provided evidence that the enzyme responsible for the exchange reaction is O-alkyl DHAP synthetase. Therefore, the present results support the hypothesis that the acyl exchange is the reverse reaction of the first step in O-alkyl DHAP synthesis; in both of these reactions the pro-R hydrogen of C-1 of the DHAP moiety of acyl DHAP and the fatty acid moiety are labilized with cleavage of the fatty acid at the DHAP C-1 to oxygen bond.
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