Pathway of phytate dephosphorylation by beta-propeller phytases of different origins.
Using a combination of high-performance ion chromatography analysis and kinetic studies, the pathway of myo-inositol hexakisphosphate dephosphorylation by the beta-propeller phytase of Shewanella oneidensis was established, which was then compared with that of Bacillus subtilis 168, Bacillus amyloliquefaciens ATCC 15841, and B. amyloliquefaciens 45 beta-propeller phytases. The data demonstrate that all of these beta-propeller phytases dephosphorylate myo-inositol hexakisphosphate in a stereospecific way by sequential removal of phosphate groups via d-Ins(1,2,4,5,6)P5, Ins(2,4,5,6)P4 to finally Ins(2,4,6)P3. Thus, the beta-propeller phytases prefer the hydrolysis of every second phosphate over that of adjacent ones. This finding does not support previous phytate degradation models proposed by J. Kerovuo, J. Rouvinen, and F. Hatzack (2000. Biochem. J. 352: 623-628) and R. Greiner, A. Farouk, M. Larsson Alminger, and N.G. Carlsson (2002. Can. J. Microbiol. 48: 986-994), but seems to fit with the structural model given by S. Shin, N.C. Ha, B.C. Oh, T.K. Oh, and B.H. Oh (2001. Structure, 9: 851-858).
Greiner
Ralf
R
Centre for Molecular Biology, Federal Research Centre for Nutrition and Food, Haid-und-Neu-Strasse 9, Karlsruhe, Germany. ralf.greiner@bfel.de
Lim
Boon L
BL
Cheng
Chiwai
C
Carlsson
Nils-Gunnar
NG
D010832:6-Phytase / Q000737:chemistry / Q000378:metabolism*; D001234:Aspergillus niger / Q000201:enzymology; D001407:Bacillus / Q000201:enzymology / Q000378:metabolism; D001665:Binding Sites; D007295:Inositol Phosphates / Q000737:chemistry / Q000378:metabolism; D007536:Isomerism; D010766:Phosphorylation; D010833:Phytic Acid / Q000737:chemistry / Q000378:metabolism*; D020592:Shewanella / Q000201:enzymology
D007295:Inositol Phosphates; D010833:Phytic Acid; D010832:6-Phytase