Open AccessPurification and characterization of NADPH‐dependent acetoacetyl‐CoA reductase from Methylobacterium extorquens
Author(s) -
Belova L.L,
Sokolov A.P,
Sidorov I.A,
Trotsenko Y.A
Publication year - 1997
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.1997.tb12740.x
Subject(s) - methylotroph , reductase , biochemistry , nad+ kinase , cofactor , chemistry , enzyme , citric acid cycle , stereochemistry , isocitrate dehydrogenase
NADPH‐dependent acetoacetyl‐CoA (AcAc‐CoA) reductase (EC 1.1.1.36) was purified to electrophoretic homogeneity from the methylotroph Methylobacterium extorquens – a producer of poly‐3‐hydroxybutyrate. The enzyme has an M r of 141 000 and consists of four identical subunits ( M r 31 000) and demonstrates absolute specificity for NADPH as cofactor. NADPH‐AcAc‐CoA reductase is inhibited by NADPH, AcAc‐CoA, NADP and NAD but is activated by isocitrate and ATP. The calculated K m values were 11.6 and 41 μM for AcAc‐CoA and NADPH, respectively. The results suggest that this enzyme plays a more important role in the coordinated operation of the tricarboxylic acid cycle and poly‐3‐hydroxybutyrate synthesis in M. extorquens than in the taxonomically related M . rhodesianum MB 126.