Purification and characterization of a phytate-degrading enzyme from germinated faba beans (Vicia faba Var. Alameda).
A phytate-degrading enzyme was purified approximately 2190-fold from germinated 4-day-old faba bean seedlings to apparent homogeneity with a recovery of 6% referred to the phytase activity in the crude extract. It behaves as a monomeric protein of a molecular mass of approximately 65 kDa. The phytate-degrading enzyme belongs to the acidic phytases. It exhibits a single pH optimum at 5.0. Optimal temperature for the degradation of sodium phytate is 50 degrees C. Kinetic parameters for the hydrolysis of sodium phytate are K(M) = 148 micromol L(-1) and k(cat) = 704 s(-1) at 35 degrees C and pH 5.0. The faba bean phytase exhibits a broad affinity for various phosphorylated compounds and hydrolyzes phytate in a stepwise manner. The first hydrolysis product was identified as D/L-myo-inositol(1,2,3,4,5)pentakisphosphate.
Greiner
R
R
Federal Research Centre for Nutrition, Centre for Molecular Biology, Haid-und-Neu-Strasse 9, D-76131 Karlsruhe, Germany. ralf.greiner@bfe.uni-karlruhe.de
Muzquiz
M
M
Burbano
C
C
Cuadrado
C
C
Pedrosa
M M
MM
Goyoaga
C
C
D010832:6-Phytase / Q000302:isolation & purification* / Q000378:metabolism; D007887:Fabaceae / Q000201:enzymology*; D018525:Germination; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007700:Kinetics; D008970:Molecular Weight; D010833:Phytic Acid / Q000378:metabolism; D010940:Plant Proteins / Q000302:isolation & purification* / Q000378:metabolism; D013696:Temperature
D010940:Plant Proteins; D010833:Phytic Acid; D010832:6-Phytase