β-hydroxyacyl-ACP dehydrase is an enzyme involved in the biosynthesis of fatty acids. It catalyzes the dehydration of β-hydroxyacyl-ACP intermediates, a key step in the elongation of fatty acid chains.
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β-hydroxyacyl-ACP dehydrase is a key enzyme in the elongation cycle of fatty acid biosynthesis, catalyzing the dehydration of β-hydroxyacyl-ACP intermediates.
The dehydration reaction catalyzed by β-hydroxyacyl-ACP dehydrase removes a water molecule from the β-hydroxyacyl-ACP intermediate, forming an α,β-unsaturated acyl-ACP species.
This unsaturated acyl-ACP intermediate is then further modified by other enzymes in the fatty acid synthase complex to elongate the growing fatty acid chain.
The dehydration reaction catalyzed by β-hydroxyacyl-ACP dehydrase is a reversible process, and the equilibrium can be shifted by the presence of other enzymes in the fatty acid synthase complex.
Disruption of the β-hydroxyacyl-ACP dehydrase enzyme can lead to the accumulation of β-hydroxyacyl-ACP intermediates and impair the overall efficiency of fatty acid biosynthesis.
Review Questions
Explain the role of β-hydroxyacyl-ACP dehydrase in the context of fatty acid biosynthesis.
β-hydroxyacyl-ACP dehydrase is a crucial enzyme in the elongation cycle of fatty acid biosynthesis. It catalyzes the dehydration of β-hydroxyacyl-ACP intermediates, removing a water molecule and forming an α,β-unsaturated acyl-ACP species. This unsaturated intermediate is then further modified by other enzymes in the fatty acid synthase complex to elongate the growing fatty acid chain. The dehydration reaction catalyzed by β-hydroxyacyl-ACP dehydrase is a reversible process, and the equilibrium can be shifted by the presence of other enzymes in the fatty acid synthase complex.
Describe how the activity of β-hydroxyacyl-ACP dehydrase can impact the overall efficiency of fatty acid biosynthesis.
The dehydration reaction catalyzed by β-hydroxyacyl-ACP dehydrase is a critical step in the elongation of fatty acid chains. If the activity of this enzyme is disrupted, it can lead to the accumulation of β-hydroxyacyl-ACP intermediates, which can impair the overall efficiency of fatty acid biosynthesis. This is because the subsequent steps in the elongation cycle rely on the presence of the unsaturated acyl-ACP species produced by the dehydration reaction. The disruption of β-hydroxyacyl-ACP dehydrase can therefore slow down or even halt the fatty acid elongation process, ultimately affecting the organism's ability to synthesize the necessary fatty acids for various cellular functions.
Analyze the significance of the reversible nature of the dehydration reaction catalyzed by β-hydroxyacyl-ACP dehydrase and how it may contribute to the regulation of fatty acid biosynthesis.
The reversible nature of the dehydration reaction catalyzed by β-hydroxyacyl-ACP dehydrase is an important feature that allows for the regulation of fatty acid biosynthesis. Since the equilibrium of this reaction can be shifted by the presence of other enzymes in the fatty acid synthase complex, the activity of β-hydroxyacyl-ACP dehydrase can be modulated to control the flux of intermediates through the elongation cycle. For example, if the demand for fatty acids is high, the equilibrium can be shifted towards the formation of the unsaturated acyl-ACP species, promoting the continuation of the elongation process. Conversely, if the demand for fatty acids is low, the equilibrium can be shifted towards the formation of the β-hydroxyacyl-ACP intermediates, slowing down the elongation cycle and conserving resources. This reversible nature of the dehydration reaction catalyzed by β-hydroxyacyl-ACP dehydrase is a key mechanism for the fine-tuning and regulation of fatty acid biosynthesis within the cell.
Related terms
Fatty Acid Synthase: A multi-enzyme complex that catalyzes the de novo synthesis of fatty acids from acetyl-CoA and malonyl-CoA.
Acyl Carrier Protein (ACP): A small, acidic protein that carries the growing fatty acid chain as a thioester during fatty acid biosynthesis.
Dehydration Reaction: A chemical reaction that removes a water molecule from a compound, often resulting in the formation of a new double bond.