[Isolation, purification and properties of acetolactate synthase from cultured Lactococcus lactis].
Acetolactate synthase catalyzing the synthesis of alpha-acetolactate was isolated from lactic acid bacteria Lactococcus lactis subsp. lactis biovar. diacetylactis 4 and purified. Acetolactate synthase was shown to be an allosteric enzyme with low affinity for the substrate: the Km for pyruvate was 70 mM. The curve relating the dependence of enzyme activity on pyruvate concentration had a sigmoid shape. The enzyme activity persisted for 24 h in the presence of stabilizers, pyruvate, and thiamine pyrophosphate. Acetolactate synthase had the pH optimums of 5.8 and 6.5-7.0 in acetate and phosphate buffers, respectively. The temperature optimum for this enzyme was 38-40 degrees C at pH 6.5. The molecular weight of acetolactate synthase was 150 kDa. In Polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate showed that the enzyme consisted of three identical subunits with a molecular weight of 55 kDa.
Kisrieva
Iu S
IuS
Bach Institute of Biochemistry, Russian Academy of Sciences, Leninskii pr. 33, Moscow, 117071 Russia.
Serebrennikov
V M
VM
Eneĭskaia
E V
EV
Zagustina
N A
NA
Bezborodov
A M
AM
D000095:Acetolactate Synthase / Q000302:isolation & purification*; D002852:Chromatography, Ion Exchange; D006863:Hydrogen-Ion Concentration; D017045:Lactococcus / Q000201:enzymology*; D008970:Molecular Weight; D013379:Substrate Specificity
D000095:Acetolactate Synthase