Poly(3-hydroxybutyrate) depolymerase

In enzymology, a poly(3-hydroxybutyrate) depolymerase is an enzyme that catalyzes the chemical reaction


 * poly[(R)-3-hydroxybutanoate]n + H2O $$\rightleftharpoons$$ poly[(R)-3-hydroxybutanoate]n-x + poly[(R)-3-hydroxybutanoate]x; x $$\rightleftharpoons$$ 1-5

Thus, the two substrates of this enzyme are poly[(R)-3-hydroxybutanoate]n and H2O, whereas its two products are poly[(R)-3-hydroxybutanoate]n-x and poly[(R)-3-hydroxybutanoate]x; x.

This enzyme belongs to the family of hydrolases, specifically those acting on carboxylic ester bonds. The systematic name of this enzyme class is poly[(R)-3-hydroxybutanoate] hydrolase. Other names in common use include PHB depolymerase, poly(3HB) depolymerase, poly[(R)-hydroxyalkanoic acid] depolymerase, poly(HA) depolymerase, poly(HASCL) depolymerase, and poly[(R)-3-hydroxybutyrate] hydrolase.

Structural studies
As of late 2007, two structures have been solved for this class of enzymes, with PDB accession codes and.