Phytase activities

Oxidation by raising the pH (to 7.5) phytase activity is switched off hydrolysis is prevented. Oxidation of L-glycerol-3-phosphate to DHAP by GPO at 55% glycerol (v/v) is quantitative. Catalase is added to suppress the build-up of hydrogen peroxide. The D-isomer is converted back into glycerol and phosphate in the last step. 

Several microbial species (in particular fungi) produce phytases (EC 3.1.3.8). The incorporation of suitable, microbially derived phytases in the diet can confer the ability to digest phytic acid on the recipient animals. This would have a threefold beneficial effect the anti-nutritional properties of phytic acid would be destroyed a lesser requirement for feed supplementation with inorganic phosphorous wottld exist and reduced phosphate levels would be present in the faeces. Several trials have confirmed that the inclusion of phytase in animal feed promotes at least some of these effects. However, the enzyme is not yet used in many cormtries. This may be explained, in part, by the fact that most microbial species only produce low levels of phytase activity which, obviously, has an effect on the cost of the finished product. It seems likely that widespread utilization of phytase within the industry will only be made possible by the production of this enzyme from recombinant sottrces, and at least two major enzyme companies are marketing such an enzyme for a nttmber of years now. 

Procedure 1 (Determination of the phytase activity) Transfer 2.00 mL of the Sample Preparation, Procedure 1, and the Phytase Reference Solutions, Procedure 1, into separate 20- x 150-mm glass test tubes. Using a stopwatch and starting at time equals zero, in the order of the series and within regular time intervals, place the tubes into a 37.0° 0.1° water bath and allow their contents to equilibrate for 5 min. At time equals 5 min, in the same order of the series and with the same time intervals, add 4.0 mL of Substrate Solution (previously equilibrated to 37.00 0.10) to each test tube. Mix, and replace in the 37.0° 0.1° water bath. At time equals 65 min, in the same order and within the same time intervals, terminate the incubation by adding 4.0 mL of Color/Stop Solution. Mix, and cool to ambient temperature. 

Lipase (Microbial) Activity for Medium- and Long-Chain Fatty Acids, (S3)105 Lysozyme Activity, (S3)106 Maltogenic Amylase Activity, 804 Milk-Clotting Activity, 805 Pancreatin Activity, 805 Pepsin Activity, 807 Phospholipase A2 Activity, 808 Phytase Activity, 808 Plant Proteolytic Activity, 810 Proteolytic Activity, Bacterial (PC), 811 Proteolytic Activity, Fungal (HUT), 812 Proteolytic Activity, Fungal (SAP), 813 Pullulanase Activity, 814 Trypsin Activity, 814 Enzyme Assays, 786 Enzyme-Hydrolyzed (Source) Protein,... 

Theodorou, C. (1958) Inositol phosphates in needles of Pinus radiata D. Don and the phytase activity of mycorrhizal fungi. Transactions of the 9th International Congress of Soil Science (Adelaide) 3, 483 90. 

Activities ( 1 standard error) determined using p-nitrophenyl phosphate and myo-inositol hexakisphosphate (phytate) as substrates for total monoesterase-APase and phytase activities, respectively (n.d.=not determined, <0.3 = limit of assay sensitivity). 

Richardson, A.E., Hadobas, P.A. and Hayes, J.E. (2000) Phosphomonoesterase and phytase activities of wheat (Triticum aestivum L.) roots and utilisation of organic phosphorus substrates by seedlings grown in sterile culture. Plant, Cell and Environment 23, 397 05. 

Seed germination decreases phytate and Increases phytase activity (Table X). A 22% decrease in phytic acid occurs during 5 days of soybean germination (62). Phytase activity in soybeans Increased 227% compared to an Increase of 907-3756% in peas. 

Changes in phytate content and phytase activity during germination of soybeans and peas ... 

Phytase activity One unit of phytase activity corresponds to the liberation of one pmol per minute of inorganic phosphorus from a solution of sodium phytate, measured at a fixed temperature and pH. 

Barrier-Guillot B., Casado R, Maupetit R.Jondreville C., Gatel F., 1996. Wheat phosphorus availability 2. In vivo study in broilers and pigs relationship with endogenous phytasic activity and phytic phosphorus content in wheat). Sci. FoodAgric., 70,69-74. 

The availability of plant phosphorus was long considered to be 30%, but numerous studies have shown this parameter to be highly variable, as it depends on endogenous phytase activity, on the proportion of phytate phosphorus in the feed materials and on the technological processes undergone by the feeds. The availability corresponds to the percentage of phosphorus utilised by the animal in comparison to a source of available phosphorus, usually monocalcium phosphate. 

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