Precipitated, coprecipitated, and carbon-mineral sorbents for isolation of exracellular catalase from Penicillium piceum F-648

摘要

The abilities of various sorbents to adsorb catalase (CAT; EC 1.11.1.6) from filtered culture liquid (FCL) of the fungus Penicillium piceum F-648 were compared. Potassium phosphate, hydroxyapatite (HAP), and coprecipitated sorbents containing calcium phosphate and magnesium hydroxide adsorbed extracellular CAT more efficiently than aluminum oxide, aluminum phosphate, or quartz sand. The enzyme was isolated from FCL of Penicillium piceum with the use of HAP and a binary coprecipitated sorbent, Ca3(PO4)2 + Mg(OH)2, 1:1 (CM). The CAT(CM) sample contained the least amount of protein admixture. Its spectra had absorption maximums at 279.6, 406.8 (Soret band), 540, 585, 636, and 703 nm and negative molar ellipticity minimums at 207 and 210-214 nm. The kinetic indices of the samples (KM, Vmax:KM, and specific activity) were intricately dependent on protein concentration in the reaction mixture. In dilute solutions, the KM and specific activities of CAT(CM) and CAT(HAP) equaled 667 and 137 mM; 300.9 x 10(4) and 30.0 x 10(4) U/mg protein, respectively. The effective velocity constants of inactivation of CAT(HAP), CAT(CM), and FCL in the reaction of H2O2 decomposition increased dramatically after dilution of samples. In the infinitely dilute solution, they were 4.30 x 10(-2), 6.46 x 10(-2), and 1.12 x 10(-2), respectively.