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)

Phosphatase activities associated with the intestinal brush border membrane (BBM) of the rat were examined histochemically in relation to the characteristic environment of the intestine, where luminal pH fluctuates drastically between alkaline and acid pH ranges. Special attention was given to intestinal alkaline phosphatase (IALP) and phytase on the BBM. Whole body fresh-frozen sections of young rats and their rapidly frozen and freeze-substituted small intestines, embedded in Technovit 7100, were processed for the histochemical demonstration of phosphatase activity at three different pH values (9.2, 7.3, and 5.2), representing the deviation of luminal pH in vivo. Either an azo-dye method or lead-salt method was employed using naphthol AS-MX phosphate and ATP as substrate, respectively. With the azo-dye method, intense phosphatase reactions were demonstrated along the BBM at all three pH ranges. Phosphatase reactions of the BBM at pH 9.2 and 7.3 were abolished by L(+)-phenylalanine, heat pre-treatment, and EDTA chelation although some reaction remained at pH 7.3 after the treatment with EDTA or L(+)-phenylalanine. Phosphatase reactions of the BBM at pH 5.2 were resistant to L(+)-phenylalanine, L(+)-tartrate, PCMB and EDTA chelation, implying that the characteristics of the enzyme responsible for phosphohydrolysis at acid pH values differed from those at higher pH values. The lead-salt method in which ATP was used as substrate revealed intense reactions--which were dependent on Mg++ and stimulated by Ca++ and resistant to L(+)phenylalanine--to be localized along the BBM at alkaline and neutral pH values, but not at acid pH values. In vitro experiments showed progressive hydrolysis of naphthol AS-MX phosphate by purified phytase at pH 5.2, in a dose-dependent manner, and suggested the possible involvement of phytase in the phosphatase reactions of the BBM at acid pH. These data indicate that the phosphatase reactions at alkaline and neutral pH values, associated with the BBM of the rat intestine, represent IALP and Mg++/ Ca++-ATPase, while those at acid pH appear to correspond to phytase activity, something which has not been demonstrated by histochemical methods despite the availability of extensive data based on biochemical analyses.
Arch Histol Cytol 2001 Dec
PMID:Phosphatase activities of rat intestinal enterocytes and their relation to diverse luminal pH, with special references to the possible localization of phytase along the brush border membrane. 1183 8

Hydrolysis of phytate in the stomach and the small intestine as influenced by intrinsic plant (wheat) and supplemented microbial phytase (A. niger) were investigated with six minipigs (40-50 kg initial BW) fitted with re-entrant-cannulas in the duodenum, 30 cm posterior to the pylorus (animals 1, 4, 5, and 6) and ileocecal re-entrant cannulas, 5 cm prior the ileocecal junction (animals 1, 2, and 3), respectively. Dietary treatments were as follows: (1) diet 1, a corn-based diet (43 U Phytase/kg DM); (2) diet 2, diet 1 supplemented with microbial phytase (818 U/kg DM) and (3) diet 3, a wheat-based diet (1192 U/kg DM). At 0730 and 1930 per animal 350 g diet mixed with 1050 ml de-ionized water were fed. Digesta were collected continuously and completely during 12 h after feeding. Duodenal recovery of dry matter and total phosphorus were 100% in the period between two feedings, irrespective of dietary treatment. In animals fed the wheat-based diet, dry matter left the stomach faster (p < 0.05) during the first hour after feeding than in animals fed the corn-based diets (41.3 vs. 31.0 and 25.8% of intake, respectively). Supplemented microbial phytase did not affect ileal dry matter digestibility of the corn-based diet. In the first hour after feeding, phosphorus concentration of the duodenal digesta of animals fed corn-based diets with or without supplemented microbial phytase (5.86, 6.19 mg total P/g DM) exceeded the dietary level considerably (4.30 and 4.21 mg total P/g DM) indicating a higher solubility of corn than wheat phosphorus in the stomach. Apparent ileal P absorption was higher (p < 0.05) in the wheat-based diet (37.6%) and corn-based diet supplemented with microbial phytase (34.3%) than in the unsupplemented corn-based diet (17.6%).
J Anim Physiol Anim Nutr (Berl) 2001 Dec
PMID:Hydrolysis of phytic acid by intrinsic plant or supplemented microbial phytase (Aspergillus niger) in the stomach and small intestine of minipigs fitted with re-entrant cannulas. 1190 64

Hydrolysis of phytate in the stomach and the small intestine as influenced by intrinsic plant (wheat) and supplemented microbial phytase (A. niger) were investigated with six minipigs (40-50 kg initial BW) fitted with re-entrant cannulas in the duodenum, 30 cm posterior to the pylorus (animals 1, 4, 5, and 6) and ileocecal re-entrant cannulas, 5 cm prior the ileocecal junction (animals 1, 2, and 3), respectively. Dietary treatments were as follows: (1) diet 1, a corn-based diet (43 U phytase/kg DM); (2) diet 2, diet 1 supplemented with microbial phytase (818 U/kg DM) and (3) diet 3, a wheat-based diet (1192 U/kg DM). At 0730 and 1930 per animal 350 g diet mixed with 1050 ml de-ionized water were fed. Digesta were collected continuously and completely during 12 h after feeding. In the duodenal digesta, 70% of the microbial phytase (diet 2) and 45% of the wheat phytase (diet 3) were recovered within 12 h after ingestion of the phytases, whereas only negligible amounts were detected in the digesta of pigs fed the phytase-poor corn-based diet 1. Most phytase activity passed through the stomach within the first hour after feeding. Microbial phytase activity at pH 2.8 was less sensitive to acidic pHs, such as those found in the stomach, than phytase activity at pH 5.3. Phytase activities in the digesta of the distal ileum did not depend either on source or amount of dietary phytase activity.
J Anim Physiol Anim Nutr (Berl) 2001 Dec
PMID:Hydrolysis of phytic acid by intrinsic plant and supplemented microbial phytase (Aspergillus niger) in the stomach and small intestine of minipigs fitted with re-entrant cannulas. 2. Phytase activity. 1190 65

Hydrolysis of phytate in the stomach and the small intestine as influenced by intrinsic plant (wheat) and supplemented microbial phytase (Aspergillus niger) were investigated with six minipigs (40-50 kg initial body weight) fitted with re-entrant cannulas in the duodenum, 30 cm posterior to the pylorus (animals 1, 4, 5 and 6) and ileocecal re-entrant cannulas, 5 cm prior the ileocecal junction (animals 1, 2 and 3), respectively. Dietary treatments were as follows: (1) diet 1, a corn-based diet [43 U phytase/kg dry matter (DM)]; (2) diet 2, diet 1 supplemented with microbial phytase (818 U/kg DM); and (3) diet 3, a wheat-based diet (1192 U/kg DM). At 07 30 h and 19 30 h, each animal was fed 350 g diet mixed with 1050 ml de-ionized water. Digesta were collected continuously and completely during a 12-h period after feeding. Mean hydrolysis rates of IP6 in the stomach as measured at the proximal duodenum of animals 1, 4, 5 and 6 were 9.0, 77.2 and 66.2% for diet 1, 2 and 3, respectively. Microbial phytase was much more effective in phytate hydrolysis than wheat phytase. Mean IP6 hydrolysis rates of the respective diets in the stomach and small intestine as measured at the distal ileum of animals 1, 2 and 3 were 19.0, 62.6 and 64.6% and were lower than treatment means of the stomach only. Differences existed between experimental animals with respect to their ability to hydrolyse IP6 in the stomach independent of the presence and source of dietary phytase. Considerable amounts of hydrolysis products occurred in both the duodenal and ileal digesta when diets 2 and 3 were fed; however, only traces were determined after ingestion of diet 1. Independent of dietary treatment, four IP5 isomers were detected, but in different amounts.
J Anim Physiol Anim Nutr (Berl) 2001 Dec
PMID:Hydrolysis of phytic acid by intrinsic plant and supplemented microbial phytase (Aspergillus niger) in the stomach and small intestine of minipigs fitted with re-entrant cannulas. 3. Hydrolysis of phytic acid (IP6) and occurrence of hydrolysis products (IP5, IP4, IP3 and IP2). 1190 66

Three phytase (EC 3.1.3.26) isoforms from the roots of 8-d-old maize (Zea mays L. var Consul) seedlings were separated from phosphatases and purified to near homogeneity. The molecular mass of the native protein was 71 kD, and the isoelectric points of the three isoforms were pH 5.0, 4.9, and 4.8. Each of the three isoforms consisted of two subunits with a molecular mass of 38 kD. The temperature and pH optima (40[deg]C, pH 5.0) of these three isoforms, as well as the apparent Michaelis constants for sodium inositol hexakisphosphate (phytate) (43, 25, and 24 [mu]M) as determined by the release of inorganic phosphate, were only slightly different. Phytate concentrations higher than 300 [mu]M were inhibitory to all three isoforms. In contrast, the dephosphorylation of 4-nitrophenyl phosphate was not inhibited by any substrate concentration, but the Michaelis constants for this substrate were considerably higher (137-157 [mu]M). Hydrolysis of phytate by the phytase isoforms is a nonrandom reaction. D/L-Inositol-1,2,3,4,5- pentakisphosphate was identified as the first and D/L-inositol-1,2,5,6-tetrakisphosphate as the second intermediate in phytate hydrolysis. Phytase activity was localized in root slices. Although phosphatase activity was present in the stele and the cortex of the primary root, phytase activity was confined to the endodermis. Phytate was identified as the putative native substrate in maize roots (45 [mu]g P g-1 dry matter). It was readily labeled upon supplying [32P]phosphate to the roots.
Plant Physiol 1996 Dec
PMID:Maize Root Phytase (Purification, Characterization, and Localization of Enzyme Activity and Its Putative Substrate). 1222 56

The mineral content of legumes is generally high, but the bioavailability is poor due to the presence of phytate, which is a main inhibitor of Fe and Zn absorption. Some legumes also contain considerable amounts of Fe-binding polyphenols inhibiting Fe absorption. Furthermore, soya protein per se has an inhibiting effect on Fe absorption. Efficient removal of phytate, and probably also polyphenols, can be obtained by enzymatic degradation during food processing, either by increasing the activity of the naturally occurring plant phytases and polyphenol degrading enzymes, or by addition of enzyme preparations. Biological food processing techniques that increase the activity of the native enzymes are soaking, germination, hydrothermal treatment and fermentation. Food processing can be optimized towards highest phytate degradation provided that the optimal conditions for phytase activity in the plant is known. In contrast to cereals, some legumes have highest phytate degradation at neutral or alkaline pH. Addition of microbial enzyme preparations seems to be the most efficient for complete degradation during processing. Fe and Zn absorption have been shown to be low from legume-based diets. It has also been demonstrated that nutritional Fe deficiency reaches its greatest prevalence in populations subsisting on cereal- and legume-based diets. However, in a balanced diet containing animal protein a high intake of legumes is not considered a risk in terms of mineral supply. Furthermore, once phytate, and in certain legumes polyphenols, is degraded, legumes would become good sources of Fe and Zn as the content of these minerals is high.
Br J Nutr 2002 Dec
PMID:Bioavailability of minerals in legumes. 1249 28

An in vitro model simulating enzymatic activity in the gastrointestinal tract was developed for the assessment of the potential bioaccessibility of Cd and Pb in cocoa powder and liquor. The model was based on the sequential extraction with simulated gastric and intestinal juices; the residue after the latter extraction was further investigated by using, in parallel, solutions of phytase and cellulase. The solubility of Cd and Pb in the corresponding enzymatic extracts was measured by ICP MS. The bioaccessibility of Cd in cocoa varied from 10 to 50% in gastrointestinal conditions. An additional 20 or 30% of Cd could be recovered by phytase and cellulase, respectively. The bioaccessibility of Pb in gastrointestinal conditions did not exceed 5-10%. Only a few percent more of this metal could be recovered by extraction with phytase and cellulase.
Analyst 2002 Dec
PMID:Development of a sequential enzymolysis approach for the evaluation of the bioaccessibility of Cd and Pb from cocoa. 1253 73

1. Non-genetically modified (non-GM) phytase product derived from Aspergillus niger possesses various side active enzymes including alpha-amylase, protease, cellulase and hemicellulase. In contrast, the product of genetically modified (GM) phytase product has much less side active enzyme since the capacity of phytase production is reinforced by gene modification. In the present study we have tried to determine whether the difference of side enzyme activity of phytase product affects growth performances and nutritive value in chicks; in addition we tried to characterise the physiological change induced by the difference of side active enzymes. 2. Single Comb White Leghorn male chicks at 7 d of age were fed on experimental barley-based diets for 10 d. The feeding trial was of a factorial design (3 x 2 x 2), having three types of dietary phytase products (control, non-GM or GM phytase products derived from A. niger at 1000 U/kg diet), two levels of dietary available P supplement (0 or 6 g/kg diet) and two levels of dietary protein (CP 180 or 120 g/kg). 3. The non-GM phytase product caused a 6% increase in final body weight and feed efficiency compared with the control and the GM phytase product without interacting with dietary protein and available P level. However, in birds given available P-free diet, both non-GM and GM phytase products induced a 20% increase in plasma P concentration, suggesting no difference in phytase activity between the non-GM and GM phytase products. 4. The balance study showed that the metabolisable energy of the non-GM phytase product (15.6 +/- 0.05 kJ/g diet) was significantly higher among the treatments (control, 15.1 +/- 0.05; GM phytase product 15.3 +/- 0.07). The non-GM phytase product also increased the rate of food passage through the crop, and caused a drastic reduction in intestinal weight, perhaps as a consequence of digestion of non-starch polysaccharides. 5. We conclude that the side active enzymes in non-GM phytase product improve growth performance and nutritive value of the diet in chicks. However, the efficacy of phytase activity should not be different between non-GM and GM phytase products.
Br Poult Sci 2002 Dec
PMID:Improvement of growth and nutritive value in chicks with non-genetically modified phytase product from Aspergillus niger. 1255 93

Expression of heterologous phytases in crops offers a great potential for improving phosphate and mineral bioavailability in food and feed. In this context it is of relevance to describe the concerted action of endogenous and hetrologous phytases on the transgenic seed inositol phosphate profile. Here we report metal-dye detection HPLC analysis of inositol phosphate degradation in flour from transgenic wheat materials possessing wheat endogenous 6-phytase [EC 3.1.3.26] and Aspergillus 3-phytase [EC 3.1.3.8] activities under the control of the maize ubiquitin-1 promoter and the wheat high molecular weight glutenin subunit 1DX5 promoter respectively. During 50 min incubation there is an accumulation of InsP5 to InsP2 breakdown products in non-transgenic material. Aspergillus niger phytase specific breakdown products are transiently detected in transgenic material but after 50 min incubation virtually all InsP5, InsP4 and InsP3 isomers are hydrolysed.
Transgenic Res 2003 Dec
PMID:Concerted action of endogenous and heterologous phytase on phytic acid degradation in seed of transgenic wheat (Triticum aestivum L.). 1471 94

The effect of starch source and phytic acid (PA) supplementation on phosphorus (P) partitioning and ruminal phytase activity was evaluated in eight midlactation cows (four ruminally cannulated). Cows were randomly assigned to treatments in replicated 4 x 4 Latin squares with four 18-d periods. Diets included dry ground corn (DG) or steam-flaked corn (SF), with no supplemental P (L; 0.33% P) or supplemental purified PA (0.44% P) to provide additional P from a nonmineral source. Total collection of milk, urine, and feces was conducted on d 16 to 18 of each period. Ruminal fluid was sampled and ruminal pH measured every 8 h on d 17 and 18. Milk yield was unaffected by starch source, despite lower DMI by cows fed SF. Cows fed SF had increased DM digestibility compared with those fed DG, and tended to have higher efficiency of milk yield (1.40 vs. 1.35 kg of milk/kg of DMI). Intake and fecal excretion of P was lower in cows fed SF than in cows fed DG. In cows fed SF, milk P as a percentage of P intake increased compared with cows fed DG. Ruminal pH was unaffected by diet, but milk fat content was lower for cows fed SF. Milk yield, DMI, and feed to milk ratio were not affected by supplementation with PA. Although cows fed PA had increased P intake compared with cows fed low P diet, increased P excretion resulted in no differences in apparent P digestibility. Phosphorus balance tended to be higher in cows fed PA, but milk P as a percentage of intake was reduced. The interaction of starch source and PA affected ruminal phytase activity. Altering starch source to improve efficiency of milk yield in lactating dairy cows may help reduce P losses from dairy farms.
J Dairy Sci 2003 Dec
PMID:The effect of steam-flaked or dry ground corn and supplemental phytic acid on phosphorus partitioning and ruminal phytase activity in lactating cows. 1474 Aug 35


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