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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. 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.
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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.
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PMID:[The effect of a supplement of microbial phytase on zinc availability]. 133 30

Phytase (myo-inositol hexakisphosphate phosphohydrolase; EC 3.1.3.8 or 3.1.3.26) was purified from rat intestinal mucosa. The purified enzyme preparation exhibited two protein bands on SDS-polyacrylamide gel electrophoresis with estimated molecular masses of 70 kDa and 90 kDa. Rabbit antisera prepared against the 90K subunit cross-reacted with the 70K subunit on immunoblotting. The peptide maps of the 70K and 90K subunits were similar, and the N-terminal amino acid sequences of the two subunit proteins were almost identical. Treatments to remove sugar moieties from the proteins showed that the two subunit proteins had different oligosaccharide chains, although the difference in their molecular masses was not due to the difference in their oligosaccharide compositions. The purified enzyme also showed activity of alkaline phosphatase (orthophosphoric monoester phosphohydrolase; EC 3.1.3.1), but the properties of the two enzyme activities were different; the optimum pH for phytase activity was 7.5, while that for alkaline phosphatase was 10.4. Phytase activity did not necessarily require divalent cations, while Mg2+ was essential for alkaline phosphatase activity. Phenylalanine, a specific inhibitor of intestine-type alkaline phosphatase had no effect on the phytase activity.
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PMID:Purification and characterization of phytase from rat intestinal mucosa. 165 10

The activities of phytase and alkaline phosphatase in the intestine gradually increased in parallel during development of rats, but the 70K and 90K subunits were expressed differentially; only the 70K subunit was detected at birth, whereas the 90K subunit appeared at the weaning period (3 weeks after birth). When rats were forced to wean at 18 days old and fed laboratory chow, the enzyme activity increased markedly and the 90K subunit appeared within 1 day. These findings suggest that weaning is involved in the change in the subunit composition. Increases in the enzyme activity and amount of the 90K subunit were significantly delayed by feeding weanling animals on casein diet, but induced significantly by feeding them on casein diet supplemented with phytate. Thus induction of the 90K subunit seems to be accelerated by intake of phytic acid in the diet. The Km value of the enzyme from suckling rats for phytate was 5.25 mM, while that of adult rats was 0.213 mM. In contrast, the Km value for p-nitrophenyl phosphate (PNPP) was constant during development. The phytase activity of suckling rats did not show a distinct pH-dependence. These findings suggest that the 90K subunit may play some important roles in expressing an efficient phytase activity.
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PMID:Developmental and dietary induction of the 90K subunit of rat intestinal phytase. 165 11

Alkaline phosphatase, highly purified from bovine intestinal mucosa, has significant hydrolytic activity against phytate and CaATP. Phytase and CaATPase activities require quite different assay conditions than those which are optimal for conventional alkaline phosphatase substrates such as 4-nitrophenyl phosphate. We have used affinity chromatography and antibody recognition to demonstrate that the phytase and CaATPase activities are not due to contaminating enzymes, but are intrinsic activities of intestinal alkaline phosphatase. All of the phytase and CaATPase activities present in crude extracts of bovine intestinal mucosa can be accounted for by alkaline phosphatase. Apparently neither phytase nor CaATPase exist in this tissue as independent enzymes. Specific substrates which require assay conditions quite different from the conventional 4-nitrophenyl phosphate substrate may account for the physiological function of "alkaline phosphatase."
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PMID:The relationship of alkaline phosphatase, CaATPase, and phytase. 299 87

At least two-thirds of the phosphorus ingested by pigs is in the form of phytates. Two intestinal vitamin D-sensitive enzymes, alkaline phosphatase and phytase, might be involved in phytate-P digestion. The effects of dietary vitamin D upon the two intestinal phosphatases and P utilization in pigs fed a high phytate-P diet are reported here. Fourteen vit. D-depleted pigs (25-hydroxy vit. D: about 2 ng/ml plasma) were divided into two groups fed the same basal diet containing 0.6% P (of which 80% was phytic) and 0.6% Ca. One group (+D) was supplemented for 5 weeks with vit. D (1 000 IU D3/kg diet) and the other (-D) received none. P absorption and retention was two times higher in +D pigs than in -D animals (balance technique), and tibia X-ray pictures showed a lower bone density with the -D diet than with the +D diet. Surprisingly, vit. D supplementation had no effect on either of the mucosal enzymes (phytase and alkaline phosphatase). It may be concluded that vit. D improves phytate-P absorption via a mechanism which does not involve an increase in the activity of the intestinal phosphatases.
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PMID:[Absence of effect of vitamin D on intestinal phytase and alkaline phosphatase: relation with phytic phosphorus in the pig]. 299 95

In contrast to corn, wheat and triticale exhibit high phytase activities. This enzyme enhances phytic phosphorus availability, as demonstrated in pigs given wheat diets. To study the utilization of triticale phosphorus in pigs, the importance of dietary phytase content and the mineral and bone disorders related to high phytate feeding, a nutritional experiment was carried out in 12 growing pigs fed either a corn- or a triticale-based diet for 6 wk. The diets were almost identical except for the cereal component; their phosphorus contents were low (0.4%) and mainly phytic. The following parameters were measured: calcium and phosphorus balances, bone and plasma contents of calcium and phosphorus, plasma vitamin D metabolites and parathyroid hormone (PTH), bone bending moments and intestinal phosphatase activities. Both diets provoked a phosphorus deficiency, but hypophosphatemia occurred less rapidly, hypercalciuria and hypophosphaturia were less marked and phosphorus availability was greater when the triticale diet was fed. This was attributed to the high phytase content of triticale because intestinal phytase and alkaline phosphatase activities were similar in pigs fed either diet. Calcium absorption was not modified by calcium retention was greater for pigs fed triticale and led to higher bone scores. In conclusion, the higher the phytase activity of the diet, the greater the phytate P availability and the lower the bone-mineral disorders.
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PMID:Importance of cereal phytase activity for phytate phosphorus utilization by growing pigs fed diets containing triticale or corn. 303 49

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.
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PMID:[Biological availability of zinc in whole grain products with different phytate contents]. 343 24

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

1. The effects of phosphorus deprivation on phytate digestibility, phosphorus utilization and intestinal phytase (EC 3.1.3.8) and alkaline phosphatase (EC 3.1.3.1) in rats were investigated. 2. P deprivation was achieved by giving rats a diet containing 3 g P/kg and resulted in hypophosphataemia, hypercalcaemia, hypercalciuria, and lower levels of P absorbed and retained, and calcium retained. 3. Rats adapted to P deprivation by increasing the digestion of total dietary-P and phytate-P. 4. Levels of intestinal alkaline phosphatase and alkaline phytase were not different between the two treatment groups. 5. P deprivation in the rats given the marginal-P diet may be a result of a lower absorption of total dietary-P or increased absorption of inositol phosphates formed during the enzymatic hydrolysis of phytate which are not readily utilized by the rat. 6. These results suggest that intestinal phytase and alkaline phosphatase do not play a role in the adaptive increase in phytate digestibility by rats given marginal-P diets. The adaptation may result from enhanced phytase or alkaline phosphatase synthesis by the gastrointestinal microflora stimulated by a lower level of P in the digesta.
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PMID:Adaptive increase in phytate digestibility by phosphorus-deprived rats and the relationship of intestinal phytase (EC 3.1.3.8) and alkaline phosphatase (EC 3.1.3.1) to phytate utilization. 629 37


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