Exam Review - Chapter 21

That catalyzes the reaction hydroxyacyl acp

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Unformatted text preview: yl group is transferred from Cys- SH gropu to the malonyl group on the –SH of ACP Use of malonyl groups makes the reaction energetically favorable Decarboxylation of the malonyl group facilitates a nucleophilic attack of the methylene carbon on the thioester linking the acetyl group to B- ketoacyl- ACP synthases (KS), displacing the enzyme’s –SH group o Step 2: Reduction (by NADPH) Acetoacetyl- ACP is reduced at the carbonyl group of C- 3 to form D- B- hydroxybutyryl- ACP • Catalyzed by β- ketoacyl- ACP reducaste Electron donor is NADPH o Step 3: Dehydration (loss of H2O) Water is now removed to yield trans- Δ- butenoyl- ACP • Enzyme that catalyzes the reaction, β- hydroxyacyl- ACP dehydratase o Step 4: Reduction (by NADPH) Double bond is reduced to form butyryl- ACP by enoyl- ACP reductase • Step 5 & 6: butyryl group is transferred from the phosphopantetheine –SH group of ACP to the Cys –SH of β- ketoacyl- ACP synthase (KS); new malonyl group attaches to the phosphopatetheine –SH gropu o ATP required to attach CO2 to acetyl- CoA and NADPH to redu...
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This note was uploaded on 02/06/2014 for the course BCHB 501 taught by Professor Jessicajones,elliottcrooke,ericgalsgow,marybethmartin during the Fall '12 term at Georgetown.

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