Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.1.3.8 (phytase)
1,997 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. In the first of 2 experiments ducklings grown from 2 to 19 d were given diets with 0, 200 or 400 g rice bran, with or without a phytase and with 1 or 3 g inorganic phosphorus (Pi) per kg for rice bran-based diets only. In the 2nd experiment rice bran concentrations were 0, 300 or 600 g rice bran per kg with or without a phytase and 1 g Pi/kg. Ducks were grown from 19 to 40 d of age. 2. In experiment 1, a response to phytase was observed for weight gain and food intake on most diets except those with 200 g rice bran (3 g Pi) and 4.00 g rice bran (1 g P)i/kg. Main effects showed that 400 g rice bran depressed growth rate and food conversion ratio (FCR); increasing Pi depressed food intake, while food phytase increased food intake and growth rate over 2 to 19 d. There were several interactions. Dry matter and P retention were reduced but N digestibility improved when rice bran was increased from 200 g to 400 g/kg at 2 to 10 d of age; apparent metabolisable energy (AME) and calcium retentions were improved, similar results being seen at 10 to 19 d of age. Calcium and P retentions increased with the addition of food phytase and, at 10 to 19 d of age, phytase increased dry matter digestibility. Increasing Pi improved calcium and P retention, but only at 2 to 10 d of age. 3. Tibia ash (g or g/kg) content of bone was lowest on the diet without rice bran and without phytase; Pi concentration had no effect but phytase increased tibia ash on diets with 0 and 200 g rice bran and 1 g Pi/kg. Retention of several minerals in tibia ash declined at the highest rice bran inclusion rate; Pi level and phytase both increased Mg retention. 4. In experiment 2, food intake and growth rate of ducks, but not FCR, declined as rice bran inclusion increased from 0 to 600 g/kg. Phytase improved growth rate but not food intake and FCR on all 3 diets. Dry matter digestibility declined with increasing rice bran inclusion, but AME increased; retention of P and Mg declined but those of Ca and Fe increased. Phytase improved dry matter digestibility and retention of N and P. AME also increased but this was only on diets with 0 and 600 g rice bran/kg. There were reductions of 8% and 10% in P excreted in experiments 1 and 2 respectively when food phytase was added. 5. Tibia ash declined with increasing dietary inclusion of rice bran. Zn and Mn in ash tended to decline and Mg to increase; Ca and P showed no change in concentration in tibia ash. Again, phytase increased tibia ash content in bone. 6. It was concluded that there were a number of unexpected benefits from adding a food phytase to these diets, which resulted in improved nutrient yield and bird performance, although several of the diets appeared to be adequate in available P.
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PMID:Strategies to improve the nutritive value of rice bran in poultry diets. III. The addition of inorganic phosphorus and a phytase to duck diets. 992 12

A novel bacterial phytase from a Bacillus amyloliquefaciens strain was crystallized using the hanging-drop vapour-diffusion method. The amino-acid sequence of the enzyme does not show any homology to those of other known phytases or phosphatases, with the exception of a phytase from Bacillus subtilis. The enzyme exhibits a thermal stability which is strongly dependent on calcium ions. High-quality single crystals of the enzyme in the absence of calcium ions were obtained using a precipitant solution containing 20% 2-methyl-2, 4-pentanediol and 0.1 M MES (pH 6.5). Native diffraction data to 2.0 A resolution were obtained from a flash-frozen crystal at 110 K using a rotating-anode X-ray source. The crystals belong to space group P212121 with unit-cell dimensions a = 50.4, b = 64.1, c = 104. 2 A and contain one monomer per asymmetric unit. Structure determination using heavy-atom derivative crystals is in progress, along with an effort to crystallize the calcium ion bound form of the enzyme.
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PMID:Preliminary X-ray crystallographic analysis of a novel phytase from a Bacillus amyloliquefaciens strain. 1008 71

1. A 3-week feeding trial with 96 sexed d-old broiler chickens was conducted to examine the effects of microbial phytase supplementation (Natuphos 5000) at 2 dietary energy concentrations on their performance, and the utilisation of nitrogen (N), phosphorus (P), calcium (Ca) and zinc (Zn) and on tibiae ash, Ca, P and Zn concentrations. Four replicate pens (6 birds per pen) of a completely randomised design were used in a 2x2 factorial arrangement of treatments with 2 contents of metabolisable energy (11.72 and 12.55 MJ ME/kg) and 2 additions of phytase (0 and 500 U of microbial phytase/kg). 2. Phytase supplementation significantly improved the utilisation of N, P, Ca and Zn (as a percentage of intake) and increased the concentration of Ca and Zn in the tibiae (P<0.05) because of higher intakes of dry matter, N, P, Ca and Zn. Phytase also significantly reduced the amount of P in the excreta (P<0.05). 3. The AME content of the diet influenced significantly (P<0.05) the excretion of N, P, Ca and Zn and the concentration of P and Ca in tibiae with the birds fed on the high AME diet excreting more minerals and having a smaller percentage of these minerals in their tibiae. However, there were strong interactions between phytase addition and AME in tibia ash and P, with the phytase supplementation producing a higher ash content at the higher AME a and a lower P content at the lower AME.
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PMID:Effects of microbial phytase on growth and mineral utilisation in broilers fed on maize soyabean-based diets. 1047 31

Differential agar media for the detection of microbial phytase activity use the disappearance of precipitated calcium or sodium phytate as an indication of enzyme activity. When this technique was applied to the study of ruminal bacteria, it became apparent that the method was unable to differentiate between phytase activity and acid production. Strong positive reactions (zones of clearing around microbial colonies) observed for acid producing, anaerobic bacteria, such as Streptococcus bovis, were not corroborated by subsequent quantitative assays. Experimentation revealed that acidic solutions generated false positive results on the selected differential medium. Empirical studies undertaken to find a solution to this limitation determined the false positive results could be eliminated through a two step counterstaining treatment (cobalt chloride and ammonium molybdate/ammonium vanadate) which reprecipitates acid solubilized phytate. This report discusses the application of the developed two step counterstaining treatment for the screening of phytase producing ruminal bacteria as well as its use in phytase zymogram assays.
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PMID:A novel staining method for detecting phytase activity. 1057 3

The objective of this study was to investigate the influence of microbial phytase and calcium supplementation to diets for growing pigs on the retention of lead in the kidney, liver, muscle, brain, and bone (phalanx 1). The experiments were carried out with barrows over the body weight range from 17 to 50 kg. The average lead concentration of the diets was 1.45 mg/kg dry matter. Diets were prepared with or without a supplement of 800 units of microbial phytase. The calcium concentration in the diets was 6.53 or 13.4 g/kg dry matter. The addition of microbial phytase showed an increase of lead concentration in bone. By increasing the calcium concentration to 13.4 g/kg dry matter, it was possible to avoid the phytase-induced increase of lead retention in bone.
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PMID:Influence of microbial phytase and dietary calcium on the accumulation of lead in different organs of pigs. 1061 63

Phytases hydrolyze phytic acid to less phosphorylated myo-inositol derivatives and inorganic phosphate. A thermostable phytase is of great value in applications for improving phosphate and metal ion availability in animal feed, and thereby reducing phosphate pollution to the environment. Here, we report a new folding architecture of a six-bladed propeller for phosphatase activity revealed by the 2.1 A crystal structures of a novel, thermostable phytase determined in both the partially and fully Ca2+-loaded states. Binding of two calcium ions to high-affinity calcium binding sites results in a dramatic increase in thermostability (by as much as approximately 30 degrees C in melting temperature) by joining loop segments remote in the amino acid sequence. Binding of three additional calcium ions to low-affinity calcium binding sites at the top of the molecule turns on the catalytic activity of the enzyme by converting the highly negatively charged cleft into a favorable environment for the binding of phytate.
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PMID:Crystal structures of a novel, thermostable phytase in partially and fully calcium-loaded states. 1065 18

The metal ion requirement of a Bacillus subtilis phytase has been studied. Removal of metal ions from the enzyme by EDTA resulted in complete inactivation. Circular dichroism spectroscopy was used to study the effect of metal ion removal on the protein conformation. The loss of enzymatic activity is most likely due to a conformational change, as the circular dichroism spectra of holoenzyme and metal-depleted enzyme were different. Metal-depleted enzyme was partially able to restore the active conformation when incubated in the presence of calcium. Only minor reactivation was detected with other divalent metal ions and their combinations. Based on the data we conclude that B. subtilis phytase requires calcium for active conformation. Calcium has also a strong stabilizing effect on the enzyme against thermal denaturation. However, the conformational change resulted by calcium depletion does not affect the protease susceptibility.
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PMID:The metal dependence of Bacillus subtilis phytase. 1067 9

Female and male turkeys were fed 110, 73, 52, and 30% of the NRC (1994) nonphytate P (NPP) requirement without and with 500 phytase units (FTU)/kg during 4 to 14 or 16 wk of age, respectively. At 110% P (control; also 110% of NRC Ca), phytase was without effect. At 73% of NPP (100% Ca), without phytase, performance was similar to the control; with phytase, performance was equivalent, and in some stages, superior to the control. At 52% of NPP (90% Ca), performance was inferior without phytase and was variably similar or poorer than the control with phytase. At 30% NPP without phytase, poults gained poorly and showed a high incidence of leg disorder at 8 wk when they were removed from experiment; poults gained better with 80% NRC Ca compared with 110%. At 30% NPP with phytase, turkeys performed remarkably well, although suboptimally, at 80 or 110% NRC Ca. Phytase at 400, 300, and 200 FTU/kg with increasing age periods performed as well as 500 FTU/kg with 73% of NRC NPP (100% Ca) and 52% NRC NPP (90% Ca). These lower phytase levels were not as sufficient as 500 FTU/kg with 30% of NRC NPP; this inadequacy was more severe with higher dietary calcium. Phytase was effective in reducing dietary P requirements of growing turkeys when the NPP levels were below NRC (1994) requirements.
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PMID:Effect of dietary phosphorus, calcium, and phytase on performance of growing turkeys. 1073 52

The localization of phytase (myo-inositol-hexaphosphate phosphohydrolase) in the ruminal bacteria, Selenomonas ruminantium JY35 and Mitsuokella multiacidus 46/5(2), was determined with transmission electron microscopy. Phosphate produced from the enzymatic dephosphorylation of the calcium salt of phytic acid is precipitated as calcium phosphate. The calcium is then replaced with lead to produce electron-dense lead phosphate. This deposition of lead phosphate localized phytase in S. ruminantium JY35 and M. multiacidus 46/5(2) to the outer membrane, and confirmed intracellular expression of the enzyme in Escherichia coli pSrP.2, the recombinant clone which possesses the gene (phyA) encoding phytase (phyA) in S. ruminantium.
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PMID:Localization of phytase in Selenomonas ruminantium and Mitsuokella multiacidus by transmission electron microscopy. 1077 78

An 18-d experiment was conducted to determine the effect of varying mix uniformity of phytase on growth performance, mineral retention, and bone mineralization in chicks. Chicks (initial and final weights were 74.5 and 803.3 g) were allotted to seven treatments with six (Treatment 1) or seven (Treatments 2 to 7) replicates of seven chicks per replicate in a completely randomized design. Varying mix uniformity of phytase was simulated by alternately providing two diets with two different concentrations of microbial phytase; the diets were switched every 24 h. Treatments were: 1) positive control (CON) (Ca, 1.0%; available phosphorus (aP), 0.45%), 2) negative control (NEG) (Ca, 0.9%; aP, 0.35%), 3) NEG + 600 phytase units (FTU) daily (CV0), 4) NEG + 500 or 700 FTU (CV17), 5) NEG + 400 or 800 FTU (CV34), 6) NEG + 200 or 1,000 FTU (CV69), or 7) NEG + 0 or 1,200 FTU (CV103). Gain, feed intake, and bone breaking strength were similar (P > 0.15) in the CON and CV0 treatments, but these response variables were decreased in the NEG treatment (P < 0.01). Gain:feed was not affected by treatment (P = 0.15). Bone ash was decreased (P < 0.02) by the NEG and CV0 treatments compared with the CON diet, but chicks fed the CV0 diet had greater bone ash than those fed the NEG (P < 0.01) diet. Increasing FTU CV decreased bone breaking strength and bone ash (P < 0.01). Calcium and phosphorus retention (P < 0.08) and gain (P < 0.09) were numerically decreased, and phosphorus excretion was numerically increased (P < 0.07) as FTU CV increased. The difference between the CV0 and CV103 treatments was significant only for bone breaking strength and ash (P < 0.01). In conclusion, increasing phytase CV had little effect on growth performance, whereas bone ash and breaking strength and calcium and phosphorus retention and excretion decreased only at the most extreme CV.
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PMID:The effect of varying mix uniformity (simulated) of phytase on growth performance, mineral retention, and bone mineralization in chicks. 1105 57


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