Complete hydrolysis of myo-inositol hexakisphosphate by a novel phytase from Debaryomyces castellii CBS 2923.
Debaryomyces castellii phytase was purified to homogeneity in a single step by hydrophobic interaction chromatography. Its molecular mass is 74 kDa with 28.8% glycosylation. Its activity was optimal at 60 degrees C and pH 4.0. The K (m) value for sodium phytate was 0.532 mM. The enzyme exhibited a low specificity and hydrolyzed many phosphate esters. The phytase fully hydrolyzed myo-inositol hexakisphosphate (or phytic acid, Ins P(6)) to inositol and inorganic phosphate. The sequence of Ins P(6) hydrolysis was determined by combining results from high-performance ionic chromatography and nuclear magnetic resonance. D. castellii phytase is a 3-phytase that sequentially releases phosphate groups through Ins (1,2,4,5,6) P(5), Ins (1,2,5,6) P(4), Ins (1,2,6) P(3), Ins (1,2) P(2), Ins (1 or 2) P(1), and inositol (notation 3/4/5/6/1 or 2).
Equipe Génie Microbiologique et Enzymatique, SUPAGRO-INRA, 2 place Viala, 34060, Montpellier Cedex 01, France.
Mélanie
M
Ragon
André
A
Aumelas
Patrick
P
Chemardin
Santiago
S
Galvez
Guy
G
Moulin
Hélène
H
Boze
D010832:6-Phytase / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism*; D002853:Chromatography, Liquid; D004795:Enzyme Stability; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007294:Inositol / Q000378:metabolism; D007700:Kinetics; D010710:Phosphates / Q000378:metabolism; D010833:Phytic Acid / Q000378:metabolism*; D004718:Saccharomycetales / Q000201:enzymology* / Q000378:metabolism*; D013379:Substrate Specificity; D013696:Temperature
D010710:Phosphates; D007294:Inositol; D010833:Phytic Acid; D010832:6-Phytase