The pathway of dephosphorylation of myo-inositol hexakisphosphate by phytases from wheat bran of Triticum aestivum L. cv. Nourin #61.
Phytases are the primary enzymes responsible for the hydrolysis of phytic acid, myo-inositol-1, 2, 3, 4, 5, 6-hexakisphosphate (InsP6). The pathway of hydrolysis of InsP6 by phytase from wheat bran of Triticum aestivum L. cv. Nourin #61 is proved in this study. Structures of the intermediates were established by a variety of nuclear magnetic resonance techniques (1H-, two-dimensional 1H-1H coupling-correlation spectra and two-dimensional 31P-1H correlation spectra), gas chromatography, and bioassay. On the basis of the structures identified, initial hydrolysis of the phosphate ester occurs at the D/L-4 position of InsP6 to yield D/L-Ins (1, 2, 3, 5, 6) P5. After the dephosphorylation, the pathway of dephosphorylation is divided into two routes. The main route proceeds via D/L-Ins (1, 2, 5, 6) P4, D/L-Ins (1, 2, 6) P3 and D/L-Ins (1, 2) P2, while the minor route proceeds via D/L-Ins (1, 2, 3, 6) P4, Ins (1, 2, 3) P3 and D/L-Ins (1, 2) P2. D/L-Ins (1, 2) P2 is hydrolyzed at the D/L-1 or 2-position, and finally myo-inositol is produced.
Nakano
T
T
Graduate School of Science and Technology, Niigata University, Niigata, Japan.
Joh
T
T
Narita
K
K
Hayakawa
T
T
D010832:6-Phytase / Q000302:isolation & purification / Q000378:metabolism*; D001681:Biological Assay; D002849:Chromatography, Gas; D004043:Dietary Fiber / Q000378:metabolism*; D004795:Enzyme Stability; D006868:Hydrolysis; D007295:Inositol Phosphates / Q000737:chemistry / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D008956:Models, Chemical; D010833:Phytic Acid / Q000302:isolation & purification / Q000378:metabolism*; D014908:Triticum / Q000201:enzymology*
D004043:Dietary Fiber; D007295:Inositol Phosphates; D010833:Phytic Acid; D010832:6-Phytase