[Isolation and properties of cytoplasmic L(+)-lactatoxydase of Candida lipolytica yeasts].
The enzyme preparation of L(+)-lactatoxydase (K.F. 1.1.3.2) with molecular weight of 230 000 has been isolated from the soluble fraction of the C. lipolytica cells and purified similar 360 times. The enzyme oxydizes L(+)-lactate, the optimum activity of the enzyme being observed at pH 8.0. Oxydation of the substrate is followed by accumulation of H2O2. Silver ions, p-chloromercurybenzoate and dicumarol inhibit the activity of L(+)-lactatoxydase. Iron complexones, cyanide and L-malate do not inhibit oxydation of the substrate. Pyruvate and its fluorine derivative practically do not produce any inhibiting effects either. The enzyme preparation contains 0.6 moles of flavin and 2 moles of nonhaem iron per a mole of the enzyme. Km value for the substrate is equal to 4-10(-4) M, Vmax--4.5 mkatom O/min/mg. Acidation of incubation medium leads to a decrease both of Km and Vmax. Km value for oxygen is equal to 3.1 mkM O2. Beside oxygen, ferricyanide, 2.6-dichlorphenolindophenol, phenazine methosulphate and cytochrome C may also serve as acceptors of L(+)-lactatoxydase electrons. The oxydized enzyme preparation is characterized by a spectrum absorption maximum at 410 nm. Upon L(+)-lactatoxydase reduction the maximum is shifted up to 420 nm.
D002175:Candida / Q000201:enzymology*; D003593:Cytoplasm / Q000201:enzymology; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D007773:Lactates; D006899:Mixed Function Oxygenases / Q000302:isolation & purification* / Q000378:metabolism; D008970:Molecular Weight; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000302:isolation & purification*
D007773:Lactates; D006899:Mixed Function Oxygenases; D010088:Oxidoreductases
Vydelenie i svoĭstva tsitoplazmaticheskoĭ L(+)-laktatoksidazy drozhzheĭ Candida lipolytica