Phosphate mediates electron transfer in pyruvate oxidase from Lactobacillus plantarum
نویسندگان
چکیده
Phosphate mediates electron transfer in pyruvate oxidase from Lactobacillus plantarum /?~ J 2tfr 6 Introduction Pyruvate oxidase from Lactobacillus plantarum (LpPOX, EC 1.2.3.3) is homotetrameric flavoenzyme with a subunit molecular mass of 65.5 kDa composed 603 residues. Each subunit contains one tightly and noncovalently bound FA thiamin diphosphate (ThDP), the biologically active form of vitamin BI. and Mg z +
منابع مشابه
Mechanism of elementary catalytic steps of pyruvate oxidase from Lactobacillus plantarum.
Single steps in the catalytic cycle of pyruvate oxidase from Lactobacillus plantarum have been characterized kinetically and mechanistically by stopped-flow in combination with kinetic solvent isotope effect studies. Reversible substrate binding of pyruvate occurs with an on-rate of 6.5 x 10(4) M(-1) s(-1) and an off-rate of pyruvate of 20 s(-1). Decarboxylation of the intermediate lactyl-ThDP ...
متن کاملActivation of thiamin diphosphate and FAD in the phosphatedependent pyruvate oxidase from Lactobacillus plantarum.
The phosphate- and oxygen-dependent pyruvate oxidase from Lactobacillus plantarum is a homotetrameric enzyme that binds 1 FAD and 1 thiamine diphosphate per subunit. A kinetic analysis of the partial reactions in the overall oxidative conversion of pyruvate to acetyl phosphate and CO2 shows an indirect activation of the thiamine diphosphate by FAD that is mediated by the protein moiety. The rat...
متن کاملThe catalytic cycle of a thiamin diphosphate enzyme examined by cryocrystallography.
Enzymes that use the cofactor thiamin diphosphate (ThDP, 1), the biologically active form of vitamin B(1), are involved in numerous metabolic pathways in all organisms. Although a theory of the cofactor's underlying reaction mechanism has been established over the last five decades, the three-dimensional structures of most major reaction intermediates of ThDP enzymes have remained elusive. Here...
متن کاملInvolvement of pyruvate oxidase activity and acetate production in the survival of Lactobacillus plantarum during the stationary phase of aerobic growth.
In addition to the previously characterized pyruvate oxidase PoxB, the Lactobacillus plantarum genome encodes four predicted pyruvate oxidases (PoxC, PoxD, PoxE, and PoxF). Each pyruvate oxidase gene was individually inactivated, and only the knockout of poxF resulted in a decrease in pyruvate oxidase activity under the tested conditions. We show here that L. plantarum has two major pyruvate ox...
متن کاملPhysiological role of pyruvate oxidase in the aerobic metabolism of Lactobacillus plantarum.
Under aerobic growth conditions Lactobacillus plantarum produced acetic acid in addition to lactic acid. It was found that lactic acid was predominantly produced at first, and then when the carbohydrate was nearly exhausted, lactic acid was metabolized further to acetic acid. The most likely enzyme involved in the aerobic metabolism of L. plantarum is pyruvate oxidase. Its activity is enhanced ...
متن کامل