Buckle K A
Department of Food Science and Technology, University of New South Wales, Kensington, Australia.
Int J Food Microbiol. 1988 Feb;6(1):67-79. doi: 10.1016/0168-1605(88)90086-4.
Rhizopus oligosporus strain CT11K2, commonly used in tempeh (fermented soybean) production produced both extra- and intracellular phytases. The enzymes were isolated from growth media and the cultured mould and partially purified by acetone fractionation, gel filtration on Sephadex G-100 and DEAE-cellulose chromatography. Intracellular phytase activity was higher than that of the extracellular enzyme. Both enzymes showed maximum activity at pH 4.5 and 55 degrees C, suggesting relatively high thermostability. The enzymes were partially inhibited by high concentrations of substrate. The Km and Vmax values of the extracellular phytase were 0.15 mM and 0.076 mumol Pi per min per ml DEAE-cellulose purified enzyme, respectively, and for the intracellular phytase were 0.17 mM and 0.34 mumol Pi per min per ml enzyme, respectively. Extracellular phytases showed inactivation and activation energies for the hydrolysis of phytic acid of approximately 28,300 cal per mol and 6100 cal per mol, respectively, while inactivation and activation energies for the intracellular phytase were approximately 33,200 per mol and 9500 cal per mol, respectively.
少孢根霉CT11K2菌株常用于制作丹贝（发酵大豆），该菌株可产生胞外和胞内植酸酶。这些酶从生长培养基和培养的霉菌中分离出来，并通过丙酮分级分离、Sephadex G - 100凝胶过滤和DEAE - 纤维素色谱法进行部分纯化。胞内植酸酶活性高于胞外酶。两种酶在pH 4.5和55℃时均表现出最大活性，表明其具有较高的热稳定性。高浓度底物会对这些酶产生部分抑制作用。胞外植酸酶的Km值和Vmax值分别为0.15 mM和每毫升DEAE - 纤维素纯化酶每分钟0.076 μmol无机磷，胞内植酸酶的Km值和Vmax值分别为0.17 mM和每毫升酶每分钟0.34 μmol无机磷。胞外植酸酶水解植酸的失活能和活化能分别约为每摩尔28,300卡和每摩尔6100卡，而胞内植酸酶的失活能和活化能分别约为每摩尔33,200卡和每摩尔9500卡。
