6533b835fe1ef96bd129fe69
RESEARCH PRODUCT
Purification and characterization of the catabolic ?-acetolactate synthase from Leuconostoc mesenteroides subsp. cremoris
V. PhalipCharles DivièsPhilippe Schmittsubject
Acetolactate synthasebiologyATP synthaseGeneral Medicinebiology.organism_classificationApplied Microbiology and BiotechnologyMicrobiologychemistry.chemical_compoundNon-competitive inhibitionchemistryBiochemistryBiosynthesisValineLeuconostoc mesenteroidesbiology.proteinIsoleucineThiamine pyrophosphatedescription
The α-acetolactate synthase from Leuconostoc mesenteroides subsp. cremoris was purified to homogeneity in SDS-PAGE. The enzyme is a trimer of 3×55,000 Da. It was unstable but could be preserved by addition of pyruvate and thiamine pyrophosphate in the buffer. The enzyme exhibits Michaelis-Menten kinetics, and Km for pyruvate is 10 mM. Three intermediates in glucose metabolism (ATP, 3-phosphoglycerate, and phosphoenolpyruvate) exhibit a noncompetitive inhibition towards the enzyme. This enzyme does not require any divalent metal ion for activity. The α-acetolactate synthase from Leuconostoc mesenteroides subsp. cremoris is not inhibited by the branched-chain amino acids (valine, leucine, and isoleucine), is FAD independent, and displays an optimal activity at pH 5.3. Therefore, it can be concluded that the purified enzyme belongs to the catabolic α-acetolactate synthases, involved in the 2,3-butanediol pathway but not in branchedchain amino acids biosynthesis.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 1995-11-01 | Current Microbiology |