Aspergillus niger pH 2.1 optimum acid phosphatase with high affinity for phytate.
An extracellular acid phosphatase isolated from the culture of a wild strain Aspergillus niger, producing the dephosphorylating 3-phytase, was obtained in a homogeneous form by sequential application of ultrafiltration through PS 50 membrane, gel filtration on Sephadex G-100 and ion exchange chromatography on DEAE-Sepharose CL 6B and CM-Sepharose CL 6B. The enzyme showed a maximum catalytic value in a strongly acidic range (pH 2.0-2.4) with pHopt 2.1 and topt 66 degrees C. The acid phosphatase showed a wide substrate specificity and a high affinity for sodium phytate, 2.5x higher than with 4-nitrophenyl phosphate. This property of the acid phosphatase demonstrated that it is a potent 3-phytase at pH 2.1 and is of great significance for a practical application of the dephosphorylating complex--its addition to the diets of monogastric animals in view of the low pH values in the digestive tract.
Gargova
S
S
Department of Biotechnology, University of Food Technologies, Plovdiv, Bulgaria. sgargova@lycos.com
Sariyska
M
M
Angelov
A
A
Stoilova
I
I
D000135:Acid Phosphatase / Q000302:isolation & purification* / Q000378:metabolism*; D001234:Aspergillus niger / Q000201:enzymology*; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D004795:Enzyme Stability; D006863:Hydrogen-Ion Concentration; D009596:Nitrophenols / Q000378:metabolism; D009943:Organophosphorus Compounds / Q000378:metabolism; D010833:Phytic Acid / Q000378:metabolism*; D013379:Substrate Specificity; D013696:Temperature; D014462:Ultrafiltration
D009596:Nitrophenols; D009943:Organophosphorus Compounds; C008644:nitrophenylphosphate; D010833:Phytic Acid; D000135:Acid Phosphatase