Comparison of the thermostability properties of three acid phosphatases from molds: Aspergillus fumigatus phytase, A. niger phytase, and A. niger pH 2.5 acid phosphatase
Article Abstract:
Research was conducted to examine the thermostabilities of three acid phosphatases and a pH 2.5 acid phosphatase through the measurement of circular dichroism, activity and fluorescence and through feed pelleting experiments. Aspergillus fumigatus phytase, A. niger phytase and A. niger pH 2.5 acid phosphatase were taken from various molds, cloned and overexpressed. Results indicate that A. fumigatus phytase and A. niger T213 phytase were not thermostable but had the ability to refold completely. A. niger T213 pH 2.5 acid phosphatase showed higher intrinsic thermostability.
Publication Name: Applied and Environmental Microbiology
Subject: Biological sciences
ISSN: 0099-2240
Year: 1998
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Gene cloning, purification, and characterization of a heat-stable phytase from the fungus Aspergillus fumigatus
Article Abstract:
The phytase-encoding gene (phyA) was cloned from Aspergillus fumigatus and overexpressed in Aspergillus niger to determine the effects of hydrogen-ion concentration (pH) and heat stability on the activity of the phosphatase. Characterization of the histidine acid phosphatase from phyA-expressing Aspergillus niger indicated the ability of the enzyme to withstand temperatures that were normally reached during the feed-pelleting process. Furthermore, the Aspergillus fumigatus phyA enzyme catalyzed phytic acid hydrolysis over a broad pH range.
Publication Name: Applied and Environmental Microbiology
Subject: Biological sciences
ISSN: 0099-2240
Year: 1997
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The phytase subfamily of histidine acid phosphatases: isolation of genes for two novel phytases from the fungi Aspergillus terreus and Myceliophthora thermophila
Article Abstract:
DNA library screening and site-directed mutagenesis were done to isolate and characterize the genes encoding phytases from two filamentous fungi, Aspergillus terreus strain 9A-a and Myceliophthora thermophila. Enzyme studies revealed that both proteins prefer phytic acid as substrate. They also demonstrated a drastically different pH optima. It was also confirmed that the two phytases belong to a novel subclass of histidine acid phosphatase family.
Publication Name: Microbiology
Subject: Biological sciences
ISSN: 1350-0872
Year: 1997
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- Abstracts: Analysis of the critical sites for protein thermostabilization by proline substitution in oligo-1,6-glucosidase from Bacillus coagulans ATCC 7050 and the evolutionary consideration of proline residues
- Abstracts: Expression of an Aspergillus niger phytase gene (phyA) in Saccharomyces cerevisiae. Molecular characterization and expression of a phytase gene from the thermophilic fungus Thermomyces lanuginosus