Transferases;
Acyltransferases;
Transferring groups other than aminoacyl groups
BRITE hierarchy

poly(R)-3-hydroxyalkanoate (3R)-3-hydroxyacyltransferase

(3R)-3-hydroxyacyl-CoA + poly[(R)-3-hydroxyalkanoate]n = CoA + poly[(R)-3-hydroxyalkanoate]n+1 [RN:R12791]

R12791;
(other) R04254
Reaction

(3R)-3-hydroxyacyl-CoA [CPD:C01086];
poly[(R)-3-hydroxyalkanoate]n [CPD:C22398]

This is the key enzyme in the biosynthesis of polyhydroxyalkanoates (PHA), linear polyesters produced by bacteria as a means of carbon and energy storage [6]. The enzyme catalyses the stereoselective, covalent linkage of (3R)-3-hydroxyacyl-CoA thioesters in a transesterification reaction with concomitant release of coenzyme A. The growing polymer is attached to a conserved active site L-cysteine residue. Three types of PHA synthases have been proposed based on their substrate specificity and enzyme structure. Type I and type III synthases preferentially polymerize short chain hydroxyalkanoate monomers containing 3-5 carbon atoms [1,2]. The difference between these two types is that type I synthases are composed of only a single subunit (PhaC), whereas type III synthases are composed of two different subunits, PhaC and PhaE [3,5]. Type II synthases are also composed of a single subunit (PhaC), but preferentially polymerize monomers containing more than 5 carbon atoms [4].

EC 2.3.1.304 created 2021