3-Hydroxy butyryl coenzyme

Steps 6-8 of Figure 29.5 Reduction and Dehydration The ketone carbonyl group in acetoacetyl ACP is next reduced to the alcohol /S-hydroxybutyry] ACP by yS-keto thioester reductase and NADPH, a reducing coenzyme closely related to NADH. R Stereochemistry results at the newly formed chirality center in the /3-hydroxy thioester product. (Note that the systematic name of a butyryl group is biitanoyl.)... 

Reduction and dehydration. The ketone carbonyl group in acetoacetyl ACP is next reduced to an alcohol by NADPH (nicotinamide adenine dinucleotide phosphate), a reducing coenzyme closely related to NADH. Subsequent dehydration of the resulting /3-hydroxy thiol ester (E2 reaction) in step 7 yields crotonyl ACP, and the carbon-carbon double bond of crotonyl ACP is further reduced by NADPH in step 8 to yield butyryl ACP. 

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