Isolation, characterization, and physiological role of the pyruvate dehydrogenase complex and alpha-acetolactate synthase of Lactococcus lactis subsp. lactis bv. diacetylactis.
AUTOR(ES)
Snoep, J L
RESUMO
The pyruvate dehydrogenase complex of Lactococcus lactis subsp. lactis bv. diacetylactis has a specific activity of 6.6 U/mg and a Km of 1 mM for pyruvate. The specific activities of E2 and E3 in the complex are 30 and 0.36 U/mg, respectively. The complex is very sensitive to NADH inhibition and consists of four subunits: E1 alpha (44 kDa), E1 beta (35 kDa), E2 (73 kDa), and E3 (60 kDa). The L. lactis alpha-acetolactate synthase has a specific activity of 103 U/mg and a Km of 50 mM for pyruvate. Thiamine pyrophosphate (Km = 3.2 microM) and divalent cations are essential for activity. The native enzyme measures 172 kDa and consists of 62-kDa monomers. The role of both enzymes in product formation is discussed in view of NADH inhibition and competition for pyruvate.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=206284Documentos Relacionados
- Identification and characterization of the alpha-acetolactate synthase gene from Lactococcus lactis subsp. lactis biovar diacetylactis.
- Dual role of alpha-acetolactate decarboxylase in Lactococcus lactis subsp. lactis.
- Cloning and expression of an alpha-acetolactate decarboxylase gene from Streptococcus lactis subsp. diacetylactis in Escherichia coli.
- Metabolic engineering of Lactococcus lactis: influence of the overproduction of alpha-acetolactate synthase in strains deficient in lactate dehydrogenase as a function of culture conditions.
- Diacetyl and α-Acetolactate Overproduction by Lactococcus lactis subsp. lactis Biovar Diacetylactis Mutants That Are Deficient in α-Acetolactate Decarboxylase and Have a Low Lactate Dehydrogenase Activity
