The importance of PHB-synthase substrate specificity in polyhydroxyalkanoate synthesis by Alcaligenes eutrophus
Year: 1989
Type: article
Abstract: INTRODUCTIONAlcaligenes eutrophus can accumulate poly-3hydroxybutyrate (PHB) or polyhydroxyalkanoate (PHA) containing only 3-hydroxybutyrate (HB) and 3-hydroxyvalerate (HV) units.Granule-associated PHB-synthase was active with D( --)-3-hydroxybutyryl-CoA and D(-)-3-hydroxyvaleryl-CoA of the range of D(--)-and L( +)-3-hydroxyacyl-CoA substrates tested (C4-Cx0).In carbonlimited cultures, PHB-synthase was predominantly soluble, becoming granule-associated on transition to nitrogen limitation.Granule-associated PHBsynthase increased in activity at least up to pH 10.0 and K m values of 0.68 mM and 1.63 mM were determined for the C 4 and C 5 substrates, respectively, at pH 8.5.The soluble PHB-synthase, which was unstable, showed equal activity in the range pH 8.0-10.0,had a K m value for o(-)-3hydroxybutyryl-CoA of 0.72 mM and an M r of 160,000.PHB does not measurably turn over under steady-state polymer-accumulating conditions.
Source: FEMS Microbiology Letters
Authors: G.W. Haywood, A.J. Anderson, E.A. Dawes
Institution: University of Hull
Language: English
Subfield: Biomaterials
Field: Materials Science
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W2061742358