• Journal of Life Science
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• v.7 no.2
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• pp.127-133
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• 1997

The phytase(myo-inositol hexkisphosphate phosphohydrolase ; EC 3.1.3.8) activity was observed only in the homogenate of intestinal mucosa, though the activity of alkaline phisphatase was measurable in various organs. In addition, no protein bands were detected in any other organs on immunoblotting using the anti-90kDa phytase antiserum. Thses results suggest that phytase is specifically present in small intestinal mucosa, and that hydrolysis of phytic acid(inositol-hexakisphosphate) can be allotted for a physiological role of the intestine-specific enzyme. The activities of phytase was increased during development of rat. The 70kDa phytase appeared just after birth, but the 90kDa phytase was not observed until adult period, suggesting that the 90kDa phytase was synthesized in response to weanling.

• Journal of Life Science
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• v.7 no.2
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• pp.119-126
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• 1997

Phytase(myo-inositol hexkisphosphate phosphohydrolase ; EC 3.1.3.8) was purified from the mucoas of rat intestinal. The molecular weight of enzyme was determined to be 160kDa by sephacryl S-200 gel filtration. Analysis of the purified enzyme o SDS-polyacrylamide gel electrophoresis(SDS-PAGE) showen that it was composed of two different subunits and the molecular weight of its subunit was found to be 70kDa and 90kDa respectively, indicating that this enzyme is hetrodimer. The enzyme activities were activated in the presence of $ MgCl_{2}$, but inhibited by $ZnCl_{2}$, $MnCl_{2}$, and EDTA. The substrates tested, phytase showed the highest affinity for the enzyme at the physiological ph. The Km value for phytic acid(inositol-hexakisphosphate)was 0.31 mM at pH 7.4. rat intestinal mucosa phytase seems to play an important in the metabolism of inositol.

• Microbiology and Biotechnology Letters
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• v.29 no.2
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• pp.78-83
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• 2001

Phytase (myo-inositol hexakisphosphate phosphohydrolase: EC 3.1.3.8) hydrolyzes phytic acid (myo-inositol hexakisphosphate) to myo-inositol and monophosphates. In order to obtain phytase producing bacteria, many samples were collected from various soils. Among thirty-five phytase-producing strains, YH100 showed the highest phytase activity. In order to identify the selected YHlOO strain, the morphological and physiological characteristics were examined according to the method of Bergey's manual by 168 rRNA sequence, cellular fatty acids profile, O+C contents and physiological test using API 20E kit. The strain YH100 identified to be a genus of Enterobacter cloacae and was named as Enterobacter cloacae YHlOO. Optimum medium for the phytase production by the Entemhacter c!o([we YHlOO was composed of 2.0%(w/v) glucose, 1.0%(w/v) peptone, 1.0%(w/v) beef extract, 0.1 %(w/v) KCI. and 0.1 %( w/v) sodium phytate.

• Journal of Microbiology and Biotechnology
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• v.12 no.2
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• pp.279-285
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• 2002

Phytase (myo-inositol hexakisphosphate phospho-hydrolase, EC 3.1.3.8) catalyzes the hydrolysis of phytate (myo-inositol hexakisphosphate) to release inorganic phosphate. A bacterial strain producing phytase was isolated from soil around a cattle shed. To identify the strain, cellular fatty acids profiles, the GC contents, a quinine-type analysis, and physiological test using an API 20NE kit were carried out. The strain was identified to be a genus of Pseudomonas sp. and named as Pseudomonas sp. YH40. The optimum culture condition for the maximum productivity of phytase by Pseudomonas sp. YH40 were attained in a culture medium composed of $1.0\%$ (w/v) glycerol, $2.0\%$ (w/v) peptone, and $0.2\%$ (w/v) $FeSO_4{\cdot}7H_2O$. Within the optimal medium condition, the production of phytase became highest after 10 h of incubation, and the maximal phytase production by Pseudomonas sp. YH40 was observed at $37^{\circ}C$ and pH 6.0.

• KSBB Journal
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• v.26 no.4
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• pp.300-304
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• 2011

Phytases are hydrolytic enzymes that catalyze the sequential hydrolysis of phytic acid (myo-inositol-1,2,3,4,5,6-hexakisphosphate) to myo-inositols with lower numbers of phosphate groups. Two types of phytases have been identified which initiate hydrolysis of the phytic acid at either the 3- or 6- position of the inositol ring. In the present investigation, a mathematical model was proposed and computed to estimate maximum enzyme reaction rate constants which fit the experimental data obtained by other authors. Although the data points were scattered to some extent, good agreement was found between the model and the experiment data. It appears that the maximum rate constants of removal of the first, second, and third phosphate groups were not equal. Also there was neither a steady trend upward or downward in the rate constants with the stepwise hydrolysis reactions.

• Journal of Animal Environmental Science
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• v.7 no.2
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• pp.83-102
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• 2001

Phytic acid (myo-inositol hexaphosphate or IP6) is the major storage form of phosphorus in cereals and legumes, representing 18 to 88% of the total phosphorus. Phytate form of phosphorus is not readily utilized by monogastric animals and this result causes pollution problem by phosporus released in areas of intensive livestock production. The interaction between phytic acid and essential dietary minerals, protein, or vitamins is considered to be one of the primary factors limiting the nutritional values of cereals and legunes in monogastric animals. Attempts have been made to hydrolyze dietary phytic acid by phytases to improve the feed quality and to decrease the amount of phosphorus excreted by animals. Phytase(myo-inositol hexakisphosphate phosphohydrolase) hydrolyzes phytic acid to myo-inositol and phosphoric acid. Two types of phytases are known: 3-phytase (EC 3.1.3.8) and 6-phytase (EC 3.1.3.26), indicating the intial attack to the susceptable phosphoester bond. Because of its great industrial importance, there is ongoing interest in isolating new bacterial strains producing novel and efficient phytases.

• Mycobiology
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• v.28 no.3
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• pp.119-122
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• 2000

Phytases (myo-inositol hexakisphosphate phosphohydrolase; EC 3.1.3.8) are enzymes which catalyze the hydrolisys of phytate into myo-inositol and inorganic phosphates. Phytases are found in plants and a variety of microorganisms. Aspergillus species were treated with 254 nm of UV irradiation for the screening of phytase overproducing mutant strains. At 15 minute irradiation, the survivals of population were less than 5%, and UV irradiation time was decided at 20 minute for the isolation of mutant strains. Four UV mutant strains in A. oryzae (YUV-47, -169, -341, -511) and six in A. ficuum (FUV-17, -36, -69, -193, -317, -419) were isolated on PSM media containing ammonium phosphate. The specific enzyme activities of A. ficuum mutants are 110 to 140% higher than that of wild type.

• Proceedings of the Ginseng society Conference
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• 2003.12a
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• pp.30-31
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• 2003

• Korean Journal of Microbiology
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• v.40 no.2
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• pp.81-86
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• 2004

Among the annotated ORFs of Streptomyces coelicolor, SCO7697 was supposed to encode for phytase (myo-inositol hexakisphosphate phosphohydrolase). The DNA fragment containing SCO7697 was cloned by the PCR from the chromosomal DNA of S.coelicolor A3(2)M. The cloned fragment was introduced into E. coli expres-sion vector, pET28a(+), to yield two recombinant plasmids, pET28-SP and pET28-LP, which were designed to encode different length of proteins. When the pET28-SP and pET28-LP were introduced into E. coli BL21, the transformants successfully overexpressed recombinant proteins, but the molecular weights of the expressed pro-teins were appeared bigger than those of expected in SDS-polyacrylamide gel electrophoresis. The shift of cul-tural temperature from 37 to $30^{\circ}C$ made most of expressed protein be solubilized. The expressed protein, however, did not show any phytase activity. When the DNA fragment with its own promoter placed on the E. coli-Streptomyces vector, pWHM3, and introduced into S. lividans, the phytase activity was not detected either. These results suggest that even though the SCO7697 was annotated as a probable phytase with high probability (E value is $6e^{-89}$), the real product doest not have phytase activity.

• Journal of Microbiology and Biotechnology
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• v.11 no.6
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• pp.1066-1070
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• 2001

The PhyA gene, encoding myo-inositol hexakisphosphate phosphohydrolase in Aspergillus niger var. awamori (wild-type), was cloned and sequenced. The cDNA was overexpressed by a multicopy gene expression system in Pichia pastoris KM71. Recombinant, wild-type and commercial phytase from Aspergilus ficuum NRRL 3135 (Natuphos) were purified. The PhyA gene of Aspergillus niger var awamori showed perfect homology to the phytase of Aspergillus ficcum and $97\%$ homology to A. niger var awamori (L02421). Wild-type phytase was highly glycosylated and more thermostable than the other two, while deglycosylated farms of three phytases showed identical molecular weight, 507 kDa. After heating at $80^{\circ}C$, wild-type, commercial, and recombinant phytases retained $57\%, 32%,\;and\;8\%$ of their original activities, respectively. In conclusion, glycosylation plays a key role in the thermostability of phytase and its enzymatic characterization.