Aspergillus ficuum

In the multi-enzyme system described by Sheldon et al. [15], the key point is the use of the phosphatase phytase from Aspergillus ficuum, which is a cheap and readily available industrial enzyme. Phytase is active at acid pH and becomes inactive at neutral pH. Thus, the pH can be used to switch on/off the activities of the various enzymes, allowing us to carry out the four-enzyme cascade in one pot. 

Immobilized phytase (from Aspergillus ficuum) has been applied in a similar manner to determine phosphate release from waters (McKelvie et al, 1995), but attempts to immobilize phosphodiesterase alone or co-immobilized with alkaline phosphatase proved unsuccessful because of loss of phosphodiesterase activity. Alkaline phosphatase, phytase and phosphodiesterase are relatively non-specific enzymes, and their use in applications such as those described above provides information on the broad functional classes of organic phosphorus compounds present. 

The lowest and the highest values for myo-inositol hexakisphosphate hydrolysis were reported in phytases of Aspergillus ficuum (pH 5.3, 0.01 mM) and in that of germinated Phaseolus aureus (0.65 mM), respectively. The highest values reported were of wheat bran phytase towards myoinositol tetrakis- and trisphosphate (5 mM see Nayini and Markakis, 1986). K and K, values for the enzymatic hydrolysis of myoinositol hexakisphosphate by different Bacillus spp. were determined to be approximately 0.44 mM and 18.6/s, respectively. The affinity of myo-inositol pentakisphosphate for the phytase enzymes and their maximal rates of hydrolysis were lower (K = 0.50-0.76 mM 7.4-16/s) than that of myo-inositol hexakisphosphate (Greiner et al., 2002). 

Shieh,T.R., Wodzinski, R.J. and Ware, J.H. (1 959) Regulation of the formation of acid phosphatases by inorganic phosphate in Aspergillus ficuum. Journal of Bacteriology 1 00, 11 51 -1155. 

Since vanadium chloroperoxidase from Curvularia inaequalis is structurally closely related to acid phosphatases and transition metal oxoanions are potent inhibitors of the related phytases, (Figure 10.8) [35,36], Sheldon and coworkers investigated the peroxidase activity of phytase from Aspergillus ficuum in the presence of sodium orthovanadate Na3V04 [37-39]. Oxidation of thioanisole with H2O2 proceeded to produce the sulfoxide in quantitative yield in the presence of [VO4]-phytase. The reaction rate showed saturation kinetics with respect to the vanadate concentration, indicating a maximum rate of 120pmol/h (TOF = 11 min ) and a dissociation constant for the vanadate ion of 15.4 pM. 

Chen, X.M. et al. 2011. Expression of Endo-Inulinase gene from Aspergillus ficuum in Escherichia coli. 

Aspergillus niger Rhizopus oligosporous Mucor recemosus A. ficuum... 

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