Stereochemistry of Δ4 dehydrogenation catalyzed by an ivy (Hedera helix) Δ9 desaturase homolog

Organic & Biomolecular Chemistry Pub Date: 2007-03-19 DOI: 10.1039/B617942H

Abstract

The stereochemistry of palmitoyl-ACP Δ4 desaturase-mediated dehydrogenation has been examined by tracking the fate of deuterium atoms located on stereospecifically monodeuterated substrates-(4S)- and (4R)-[4-2H1]-palmitoyl-ACP and (5S)- and (5R)-[5-2H1]-palmitoyl-ACP. It was found that the introduction of the (Z)-double bond between C-4 and C-5 of a palmitoyl substrate occurs with pro-R enantioselectivity—a result which matches that obtained for a closely related homolog-castor stearoyl-ACP Δ9 desaturase. These data show that despite the difference in regioselectivity between the two enzymes, the stereochemistry of hydrogen removal is conserved.

Graphical abstract: Stereochemistry of Δ4 dehydrogenation catalyzed by an ivy (Hedera helix) Δ9 desaturase homolog
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