Isolation, characterization, and physiological role of the pyruvate dehydrogenase complex and alpha-acetolactate synthase of Lactococcus lactis subsp. lactis bv. diacetylactis

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 con...

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Bibliographic Details
Published in:Journal of Bacteriology 1992-07, Vol.174 (14), p.4838-4841
Main Authors: Snoep, J.L. (University of Amsterdam, Amsterdam, Netherlands), Mattos, M.J.T. de, Starrenburg, M.J.C, Hugenholtz, J
Format: Article
Language:English
Subjects:
Acetolactate Synthase - isolation & purification
Acetolactate Synthase - metabolism
ACIDE PYRUVIQUE
ACIDO PIRUVICO
ACTIVIDAD ENZIMATICA
ACTIVITE ENZYMATIQUE
Bacteriology
Biological and medical sciences
Biotechnology
Cations, Divalent - metabolism
Chromatography, High Pressure Liquid
Fundamental and applied biological sciences. Psychology
Kinetics
LACTOCOCCUS LACTIS
Lactococcus lactis - enzymology
Lactococcus lactis lactis
LIGASAS
LIGASE
Metabolism. Enzymes
Microbiology
NAD - metabolism
OXIDORREDUCTASAS
OXYDOREDUCTASE
Pyruvate Dehydrogenase Complex - isolation & purification
Pyruvate Dehydrogenase Complex - metabolism
Pyruvates - metabolism
Pyruvic Acid
Thiamine Pyrophosphate - metabolism
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Summary: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 micromolar) 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
ISSN:0021-9193
1098-5530
1067-8832
DOI:10.1128/jb.174.14.4838-4841.1992