Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.3.8 (phytase)
 1,997 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. The activities of alkaline phosphatase (EC 3.1.3.1) and phytase (EC 3.1.3.8) were similarly distributed in the small intestine of rats. Regional differences in activity were reflected by similar differences in the capacity of ligated intestinal segments to hydrolyse phytate in vivo. Activities were greatest in the duodenum and lowest in the terminal ileum. 2. Specific activities of both enzymes were tenfold greater in the brush border fraction of duodenal mucosa compared with entire mucosal homogenates. 3. Brush-border alkaline phosphatase and phytase activities required both magnesium and zinc ions for maximal activity. 4. Zn deficiency induced by feeding a diet low in Zn (0.5 mg Zn/kg) caused similar reductions in activity of both enzymes. 5. Zn deficiency induced by feeding diets marginally adequate in Zn (12 mg/kg) and phytate (10 g/kg) caused reductions in alkaline phosphatase, phytase activities and phytate hydrolysis in vivo. 6. It is suggested that phytase activity is a manifestation of alkaline phosphatase and the significance of this in relation to phytate-induced in Zn deficiency is discussed.
 ...
PMID:The similarity between alkaline phosphatase (EC 3.1.3.1) and phytase (EC 3.1.3.8) activities in rat intestine and their importance in phytate-induced zinc deficiency. 20 27

A study of 35 (5 x 7) male, individually housed, albino rats (initial average weight = 50 g) was undertaken to examine the effect of an addition of microbial phytase to a diet containing phytate on the availability of zinc. The rats were fed a semisynthetic diet based of egg white and cornstarch over a 3-week period. All diets were supplemented with 20 mg Zn/kg. Group I (control) was fed the basal diet free of phytic acid (PA) and phytase. By replacing cornstarch by Na-phytate (0.5% in group II and 1.0% group III), molar phytate: Zn ratios of 25 and 50:1 were obtained, respectively. In groups IV (0.5% PA) and V (1.0% PA) 1000 U of microbial phytase were added. A molar phytate:Zn ratio of 25 (group II) and 50:1 (group III) resulted in a dose-dependent depression of growth and feed efficiency ratio. These negative effects of the addition of PA could be completely counteracted by the supplementation of 1,000 U of phytase in group IV and partially so in group V. Similarly, the apparent absorption and retention of Zn, Zn-concentration in femur and testes and different Zn-status-parameters in plasma (Zn-concentration, percent unsaturated plasma-Zn binding capacity, activity of alkaline phosphatase) were improved by adding 1,000 U microbial phytase/kg diet. The present study shows that an addition of microbial phytase to phytate-rich diets considerably improves the availability of Zn in growing rats.
 ...
PMID:[The effect of a supplement of microbial phytase on zinc availability]. 133 30

Phytate is one of the major inhibiting factor for zinc and iron absorption. When phytate is hydrolyzed during the food process the mineral availability is increased. By activation of the endogenous enzyme phytase which is present in plant foods, or addition of phytase, phytate is degraded to various inositolphosphates containing 1-5 phosphate groups per an inositol molecule. The effects of degradation products of phytate on availability of zinc, calcium and iron have to be further investigated. Food processes including soaking, germination and fermentation were under optimal conditions demonstrated to completely reduce the phytate content of cereals and vegetables. The results were related to in vitro measurements of iron availability and human iron and zinc absorption studies.
 ...
PMID:The effect of food processing on phytate hydrolysis and availability of iron and zinc. 165 32

Inositol compounds with three to five phosphate groups (IP3-IP5) were produced by hydrolysis of phytate (inositol hexaphosphate, IP6) and their binding affinities for calcium and zinc investigated at neutral pH with relative concentrations that had been found in a range of students' meals. Zn solubility was negligible at many of these concentrations, with less Zn bound to precipitates of Ca-IP6 than Ca-IP5. The capacity to precipitate Zn at these ratios fell between IP5 and IP3. Zn was partially desorbed by soluble chelators (histidine and picolinate), especially when it had been adsorbed to preformed Ca-IP precipitates. A lower proportion of Zn was accessible to soluble chelators from Ca-IP4 than the other compounds. IP3-IP4 were hydrolysed by phytase more readily than IP5-IP6.
 ...
PMID:Binding of zinc and calcium to inositol phosphates (phytate) in vitro. 240 Jul 62

Due to its high phytate content, the bioavailability of zinc in whole meal cereal products is distinctly lower as compared to foods of animal origin. The effect of reducing the phytate content of cereal products made from rye and wheat on growth, zinc content of femur and blood serum, as well as on the activity of serum alkaline phosphatase was investigated during a 3-week feeding trial in growing rats. The reduction of phytate was achieved by controlling the phytase activity originally present in cereals. By these treatments, the molar phytic acid/zinc ratio in the cereal products was reduced from 27-37 to 3-18. The four parameters under investigation showed a significant improvement in zinc bioavailability with decreasing phytic acid/zinc ratios. The relevance of these results for man and the value of the molar phytic acid/zinc ratio as an indicator of the bioavailability of zinc in foods are discussed.
 ...
PMID:[Biological availability of zinc in whole grain products with different phytate contents]. 343 24

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.
 ...
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

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.
 ...
PMID:Hydrolysis of the phytate of wheat flour during breadmaking. 626 49

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.
 ...
PMID:A Zn2+ binding constituent of fababeans. 626 94

Studies were conducted with corn-soybean meal diets to evaluate the effects of phytate phosphorus utilization on zinc absorption and retention in broiler chicks. In the first two experiments, zinc-65 was used to determine zinc absorption. Experiment 1 was a 2 x 2 factorial with 0 or 5 micrograms/kg dihydroxycholecalciferol and 0 or 40 ppm supplemental zinc. In Experiment 2, 5 micrograms/kg 1,25-dihydroxycholecalciferol [1,25-(OH)2D3] or 750 units/kg phytase or both were added to a diet containing 35 ppm zinc. The diets in Experiment 3 were similar to Experiment 2 except that 600 units/kg phytase was fed. Experiment 4 was similar to Experiment 3 except that dietary phosphorus was decreased by .15%. There were no treatment effects on body weight in Experiments 1 and 2. Zinc absorption was higher in zinc-deficient birds in Experiment 1, but there were no other effects on zinc-65 absorption or retention. Body weight was increased by 1,25-(OH)2D3 in Experiments 3 and 4 and by phytase in Experiment 4. Phytate phosphorus retention was increased by phytase and 1,25-(OH)2D3 and was increased additively when both sources were fed. Dietary 1,25-(OH)2D3 increased zinc retention at times during Experiments 3 and 4, but this response was inconsistent. Phytase did not affect zinc retention. Phytase plus 1,25-(OH)2D3 increased zinc retention synergistically in Experiment 3. Bone zinc was increased by 1,25-(OH)2D3 and phytase, and there was an additive effect in Experiment 3. Plasma zinc and alkaline phosphatase were not affected. The results suggest that supplemental zinc may be decreased in a corn-soybean meal diet when phytate phosphorus utilization is enhanced.
 ...
PMID:Effects of 1,25-dihydroxycholecalciferol and phytase on zinc utilization in broiler chicks. 797 76

The effect of the addition of microbial phytase to a diet based on field beans (30%), wheat (28%), peas (25%), and barley (14%) was studied in a 2-week experiment with 3 x 8 castrated male, individually housed, hybrid piglets (live weight range 12-16 kg). All diets contained about 4.7 g Ca, 4.2 g P (77% present as phytate phosphorus), 1.0 g Mg, 60 mg Zn per kg diet, and 17% crude protein. Group I was fed the basal diet with a native phytase-activity of about 260 U per kg diet. In group II, 350 U, in group III, 700 U of microbial phytase per kg diet were added. The addition of microbial phytase improved the apparent P absorption (% of intake) from 48% (group I) to 66% (group II) and 71% (group III). Comparable positive effects from the phytase treatment were obtained for the calcium utilization. The phytase supplementation also enhanced plasma zinc concentration significantly. The concentration of inorganic phosphorus in plasma, the zinc digestibility, and the magnesium balance were improved in tendency. The utilization of nitrogen remained unchanged.
 ...
PMID:Dietary effect of phytogenic phytase and an addition of microbial phytase to a diet based on field beans, wheat, peas and barley on the utilization of phosphorus, calcium, magnesium, zinc and protein in piglets. 807 7


1 2 3 4 5 6 7 8 9 10 Next >>