Characteristics of fungal phytases from Aspergillus fumigatus and Sartorya fumigata.
Aspergillus fumigatus phytase has previously been identified as a phytase with a series of favourable properties that may be relevant in animal and human nutrition, both for maximising phytic acid degradation and for increasing mineral and amino acid availability. To study the natural variability in amino acid sequence and its impact on the catalytic properties of the enzyme, we cloned and overexpressed the phytase genes and proteins from six new purported A. fumigatus isolates. Five of these phytases displayed < or= 2 amino acid substitutions and had virtually identical stability and catalytic properties when compared with the previously described A. fumigatus ATCC 13073 phytase. In contrast, the phytase from isolate ATCC 32239 ( Sartorya fumigata, the anamorph of which was identified as A. fumigatus) was more divergent (only 86% amino acid sequence identity), had a higher specific activity with phytic acid, and displayed distinct differences in substrate specificity and pH-activity profile. Finally, comparative experiments confirmed the favourable stability and catalytic properties of A. fumigatus phytase.
Brugger
R
R
Biotechnology Department, Roche Vitamins Ltd, Building 203/17B, 4070 Basel, Switzerland.
Simões Nunes
C
C
Hug
D
D
Vogel
K
K
Guggenbuhl
P
P
Mascarello
F
F
Augem
S
S
Wyss
M
M
van Loon
A P G M
AP
Pasamontes
L
L
D010832:6-Phytase / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D000595:Amino Acid Sequence; D019943:Amino Acid Substitution / Q000502:physiology; D001232:Aspergillus fumigatus / Q000201:enzymology*; D002384:Catalysis; D004795:Enzyme Stability; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology; D006863:Hydrogen-Ion Concentration; D008969:Molecular Sequence Data; D010833:Phytic Acid / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D016415:Sequence Alignment; D013379:Substrate Specificity
D005656:Fungal Proteins; D011994:Recombinant Proteins; D010833:Phytic Acid; D010832:6-Phytase