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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)

Two generations of red cells (embryonic and definitive), different types of haemoglobins, and special organic phosphates involved in the control of haemoglobin oxygenation (2:3-bisphosphoglycerate, BPG, and inositol-5-phosphate, IP5), have been found progressively during development of the chick. Levels of both organic phosphates, as well as activities of the enzymes involved in BPG synthesis (2:3-bisphosphoglycerate synthase, BPGM) and IP5 formation (phytase), were studied in the erythrocyte populations from embryo, young and adult chickens. Measurement of specific activities of BPGM and phytase in the two subpopulations present in young chickens showed that these phosphates could be specifically and predominantly formed in these two red cell populations.
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PMID:Synthesis and levels of organic phosphates in erythrocytes during avian development: specific formation of BPG and IP5 in two distinct populations from young chicks. 609 74

Low-phytate wheat bran was produced by enzymatic hydrolysis and extraction. Rat bioassay methods were utilized to determine bioavailability of iron and zinc in the low-phytate brans and to study the effect of dietary phytate/zinc molar ratio on zinc bioavailability when the phytate source was bran. Endogenous phytase activity hydrolyzed 80-100% of the phytate when wheat bran was incubated in water overnight. The relative biological values of the iron in raw bran and phytate-free bran were 98 and 113, respectively, compared to 100 for ferrous ammonium sulfate in a hemoglobin repletion assay. Low-phytate brans with phytate/zinc molar ratios of 8 or less were equivalent to zinc sulfate as dietary sources of zinc for growth of rats. Rats fed diets that contained wheat bran with zinc sulfate added to reduce the dietary phytate/zinc molar ratio from 40 or 50 to 20 grew at the same rate as rats fed a phytate-free diet, but femur zinc values were lower than those in the reference group. Gel filtration chromatography of extracts of raw and low-phytate brans suggested that zinc might be associated with phytate in wheat bran.
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PMID:Bioavailability to rats of iron and zinc in wheat bran: response to low-phytate bran and effect of the phytate/zinc molar ratio. 625 2

Some properties of phytase from cotton plant seeds were studied. The phytase activity was shown to increase during seed germination. The enzyme from cotton sprouts is not activated by Ca2+, Mg2+ and K+ and has the pH optimum of 5,0 and temperature optimum of 50 degrees. The molecular weight of the enzyme as determined by gel-filtration is 36000.
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PMID:[Some properties of cotton plant phytase]. 626 70

1. Differences in the extent of breakdown of phytate in wholemeal and white flours prepared from three wheats when the flours were made into bread using the three main UK commercial breadmaking processes were investigated. 2. The extent of breakdown (31-46% for wholemeal breads, 88-99% for white breads) was not proportional to the relative processing times involved (1-4 h). The importance of destruction of phytate in the oven is stressed. 3. The phytase (myo-inositol hexaphosphate phosphohydrolase, EC 3. 1. 3.8) activities of the wholemeal flours and the yeast were determined. Re-examination of some information in the literature enabled the relative importance of these activities, and of the various stages of breadmaking, in determining the extent of hydrolysis of phytate to be assessed. 4. Average values for the molar ratio, phytate: zinc, of 22:1 and 0.8:1 were calculated for wholemeal and white breads respectively. The nutritional significance of these results is discussed.
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PMID:Hydrolysis of the phytate of wheat flour during breadmaking. 626 49

The effects of whole wheat bran and its components on the absorption of nonheme dietary iron were measured using a double isotope technique in human volunteers. When 12 g bran was added to a light meal, absorption decreased by 51 to 74%; this inhibitory effect of bran was shown for meals of both high and low iron availability. Inhibition was not explained by monoferric phytate, the major form of iron in bran, because labeled iron from monoferric phytate was absorbed at least as well as the common pool of nonheme dietary iron. Furthermore, removal of phytate from bran by endogenous phytase did not in itself alter the inhibitory effect of the bran on iron absorption. Studies in which dephytinized bran was separated into a soluble, phosphate-rich fraction and an insoluble, high-fiber fraction indicated that the soluble fraction was more inhibitory than the insoluble fraction.
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PMID:The inhibitory effect of bran on iron absorption in man. 626 27

Binding of Zn2+ by an aqueous extract of fababeans was estimated spectrophotometrically. Treatment of the extract with phytase removed virtually all of the phytate and about 82% of the Zn2+ binding. Gel permeation chromatography of the extract showed that the Zn2+ binding factor eluted at the same volume as phytate. The major Zn2+ binding constituent of the bean extract appears to be phytate.
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PMID:A Zn2+ binding constituent of fababeans. 626 94

The separation of cells with different ages from erythrocyte populations of adult rats and young or adult chickens have been achieved by counter-current distribution (CCD). A thin-layer CCD apparatus has been employed. Erythrocytes from blood samples taken at different times after 59Fe i.p. injection were separated by CCD. By compilation in a "composite curve" of the hemoglobin and radioactivity CCD profiles obtained for each erythrocyte population, the distribution of cells according to age can be inferred. Young erythrocytes of rats are located at the right part of the CCD curves, while older cells are distributed towards the left. An opposite distribution has been found for erythrocytes from adult or young chickens. As a first attempt for the application of the CCD procedure to the assay of enzyme activities, it was found a decrease in phytase activity as the age of chicken erythrocytes increases and an increase in phosphoglycerate kinase and phosphofructokinase as the age of rat erythrocytes increases.
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PMID:Separation by counter-current distribution of rat and chicken erythrocytes of different age, and its application to the assay of enzyme activities. 627 18

Studies were made of the effects of pre- and post-weaning undernutrition and/or protein deficiency on intestinal phytase and phosphatase activities in albino rats and reversibility of the same by subsequent dietary rehabilitation. Neonatal undernutrition induced by rearing the pups in litters of 16 caused a marked decrease in alkaline phytase activity (as compared to those reared in litters of 8), while acid phytase activity decreased to a lesser extent and acid and alkaline phosphatase activities did not change. When neonatally undernourished rats were subsequently continued on a 4 or a 20% protein diet in restricted amounts (2.5 g/day) for 6 weeks the decreases in the alkaline phytase activity but not in that of acid phytase were further aggravated. Acid and alkaline phosphatases were not influenced by these treatments either. On dietary rehabilitation of these rats for subsequent 6 weeks on a 20% protein diet (ad libitum) acid and alkaline phytase activities of intestine recovered partially. These studies indicate the importance of alkaline phytase activity as a marker of intestinal maturation and is also suggestive of interrelationships between nutrition, intestinal development and its alkaline phytase activity.
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PMID:Effects of nutritional deficiencies during neonatal and post-weaning period on rat intestinal phytase and phosphatase activities. 627 91

An enzyme which liberates Pi from myo-inositol hexaphosphate (phytic acid) was shown to be present in culture filtrates of Bacillus subtilis. It was purified until it was homogeneous by ultracentrifugation, but it still showed two isozymes on polyacrylamide gel electrophoresis. The enzyme differed from other previously known phytases in its metal requirement and in its specificity for phytate. It had a specific requirement for Ca2+ for its activity. The enzyme hydrolyzed only phytate and had no action on other phosphate esters tested. This B. subtilis phytase is the only known phytate-specific phosphatase. The products of hydrolysis of phytate by this enzyme were Pi and myo-inositol monophosphate. The enzyme showed optimum activity at pH 7.5. It was inhibited by Ba2+, Sr2+, Hg2+, Cd2+, and borate. Its activity was unaffected by urea, diisopropylfluorophosphate, arsenate, fluoride, mercaptoethanol, trypsin, papain, and elastase.
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PMID:Purification and properties of phytate-specific phosphatase from Bacillus subtilis. 628 90

In mammals, bisphosphoglycerate-synthase activity, whose assay methods are previously discussed, increases gradually along erythropoiesis, leading to a consequent enhancement of 2,3-bisphosphoglycerate formation. Avian erythrocytes, on the other hand, contain inositol-pentaphosphate as major organic phosphate starting from egg eclosion, which substitutes embrionary ATP and 2,3-BPG in the regulatory function. The IHP of phytase and the disappearance of 2,3-BPG synthesis, also inhibitor of enzyme activity, should be considered responsible for IPP accumulation.
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PMID:[Metabolism of the organic phosphate regulators of oxygenation in cells of the erythrocyte series in birds and mammals]. 629 20


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