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Phytate, or phytic acid (myo-inositol 1,2,3,4,5,6-hexakis
dihydrogen phsophate), is a major phosphorous storage compound
found in plants, which plays an important role in
providing phosphorus during seed germination. The inositol ring
also plays a role in signal transduction involving calcium
channels. Simple-stomached animals are unable to digest phytate.
Thus inorganic phosphorus must be supplemented to animal diets
to meet their phosphorus requirement. Much of undigested feed
phosphorus is lost in the feces, causing eutrophication and
phosphorus pollution.
Our research involves the
use of phytases, a group of phosphohydrolases that hydrolyze the
phosphmonoester bonds of phytic acid, releasing inorganic
phosphorous in a stepwise manner, for animal and human
nutrition. Phytases can be used to replace the inorganic
phosphorus supplemention currently required for animal feeds, by
making the naturally occurring phytate phosphorus bioavailable.
This in turn reduces the phosphorus in the excreta, preventing
eutrophication. Phytase also has application to human nutrition,
as phytate in human diets is an antinutritive factor, chelating
divalent cations, such as iron and zinc, making them unavailable
for absorption. Our lab has focused
on protein engineering of phytase. Currently, we are attempting to
improve thermostability and pH profile of Escherichia coli AppA2 and
Aspergillus niger PhyA. We have taken different
approaches such as site-directed mutagenesis and directed
evolution to achieve our goal. We are also working on searching
new sources of phytase such as a plant phytase gene.
Relevant PDF file :
(Posted by Cornell University)
A NEW PHYTASE ENZYME TO BENEFIT THE ENVIRONMENT, NATURAL
RESOURCES ... |
Alpha-beta turn structure of
phytase modeled by Dr. Jaffor Ullah(Nat. Struct.
Biol. 4(3),185-190,1997)
|
Alpha-beta turn structure
of phytase modeled by Dr. Jaffor Ullah(Nat.
Struct. Biol. 4(3),185-190,1997) |
