A Calcium-Activated Phytase from Pollen of <i>Lilium longiflorum</i>

Scott, Jonathan J.; Loewus, Frank A.

doi:10.1104/pp.82.1.333

Cited by 59 publications

(27 citation statements)

References 6 publications

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“…Phytases which are relatively specific for phytic acid have been isolated from Typha lattifolia pollen (9) and Lilium longiflorum pollen (2,16). Solubilization ofthe L. longiflorum phytase was greatly enhanced by extraction with nonionic detergents.…”

Section: Seedsmentioning

confidence: 99%

Alkaline Phytase Activity in Nonionic Detergent Extracts of Legume Seeds

Scott¹

1991

Plant Physiol.

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Alkaline phytase activity, with a pH optimum of 8, was recovered from detergent extracts of dormant seeds of nine vaneties of Phaseolus vulgaris L., Pisum sativum L. var. Early Alaska, and Medicago sativa L. This alkaline phytase of legume seeds was activated by calcium and differed from most seed phytases in its relative insensitivity to inhibition by fluoride. activity differed from the pH 5 phytase in its relative insensitivity to inhibition by fluoride and the more pronounced enhancement of its activity by calcium. MATERIALS AND METHODS SeedsMany plant seeds contain significant amounts of phytic acid (myo-inositolhexakisphosphoric acid) which is degraded during germination by one or more phytases (myo-inositolhexakisphosphoric acid phosphohydrolase) (15). Phytic acid thus serves as an important store of phosphate and inositol, which is mobilized during seed germination. There is evidence that phytic acid also serves as an important antioxidant, contributing to the longevity of dormant seeds by preventing lipid peroxidation (8).Seeds contain both constitutive phytase activity and phytases that are synthesized de novo during germination (14). Most seed phytases which have been studied to date belong to a special class ofnonspecific acid phosphatases with optimal activity between pH 4.0 and 5.6. In addition to phytic acid hydrolysis, these enzymes are able to hydrolyze a variety of natural and synthetic phosphate esters. In terms of the rate of hydrolysis, phytic acid has occasionally been shown to be one of the poorer substrates for seed phytase (1 1, 13).Phytases which are relatively specific for phytic acid have been isolated from Typha lattifolia pollen (9) Preparation of Seed ExtractsFor preparation of extracts for phytase analysis, 10 g of seeds were ground to a fine powder in a prechilled mortar and pestle. To this powder, 100 mL of chilled extraction buffer [0.02 M Tris-HCl (pH 7.6) containing 0.1 % Triton X-100] was added along with 5 g of acid-washed sand. The mixture was homogenized until a uniform slurry was obtained and then centrifuged at 12,000g for 30 min at 4°C. The supernatant was dialyzed overnight at 4°C against the TrisHCl buffer (pH 7.6) without Triton X-100. The dialyzed extracts were used for phytase assays without further purification. Phytase AssaysThe reaction mixture for phytase assay contained 0.

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Section: Seedsmentioning

confidence: 99%

Alkaline Phytase Activity in Nonionic Detergent Extracts of Legume Seeds

Scott¹

1991

Plant Physiol.

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“…Recently, alkaline phytases having a pH optimum at eight were extracted by a non-ionic detergent from legume seeds (Scott 1991). Another alkaline phytase with a pH optimum at 8 was found in mature lily pollen (Hara et al 1985;Scott and Loewus 1986). Phytases show broad substrate specificity with highest affinity for phytic acid.…”

Section: Properties Of Phytasesmentioning

confidence: 99%

Reduction of phytic acid and enhancement of bioavailable micronutrients in food grains

2013

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More than half of the world populations are affected by micronutrient malnutrition and one third of world's population suffers from anemia and zinc deficiency, particularly in developing countries. Iron and zinc deficiencies are the major health problems worldwide. Phytic acid is the major storage form of phosphorous in cereals, legumes, oil seeds and nuts. Phytic acid is known as a food inhibitor which chelates micronutrient and prevents it to be bioavailabe for monogastric animals, including humans, because they lack enzyme phytase in their digestive tract. Several methods have been developed to reduce the phytic acid content in food and improve the nutritional value of cereal which becomes poor due to such antinutrient. These include genetic improvement as well as several pre-treatment methods such as fermentation, soaking, germination and enzymatic treatment of grains with phytase enzyme. Biofortification of staple crops using modern biotechnological techniques can potentially help in alleviating malnutrition in developing countries.

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“…Calcium activation in HAP phytases is not unprecedented. As an example, similar to PhylA, the phytase from the pollen grains of Lilium longiflorum is activated by Ca 2ϩ at 2 mM and inhibited by EDTA (17).…”

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Novel Phytases from Bifidobacterium pseudocatenulatum ATCC 27919 and Bifidobacterium longum subsp. infantis ATCC 15697

Tamayo-Ramos

Sanz‐Penella

Yebra

et al. 2012

Appl Environ Microbiol

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Two novel phytases have been characterized from Bifidobacterium pseudocatenulatum and Bifidobacterium longum subsp. infantis. The enzymes belong to a new subclass within the histidine acid phytases, are highly specific for the hydrolysis of phytate, and render myo-inositol triphosphate as the final hydrolysis product. They represent the first phytases characterized from this group of probiotic microorganisms, opening the possibilities for their use in the processing of high-phytate-content foods. Phytases are a special class of phosphatases that catalyze the sequential hydrolysis of myo-inositol hexakis phosphate (InsP 6 ) or phytate, the major form of phosphorous storage in plants, to lower myo-inositol phosphate derivatives. Based on biochemical properties and amino acid sequence, phytases can be categorized into two major classes, the histidine acid phytases and the alkaline phytases (9). The use of commercial phytases of fungal origin (usually Trichoderma and Aspergillus strains) is a common practice in animal feeding for improving the bioaccessibility of minerals (zinc, iron, calcium, and magnesium) that are otherwise chelated by InsP 6 and InsP 5 and insolubilized (4, 13). The presence of phytase activity has recently been reported to occur in the human intestinal Bifidobacterium pseudocatenulatum ATCC 27919 and Bifidobacterium longum subsp. infantis ATCC 15697 strains (5, 7). These bacteria were included in the production process of whole-wheat bread, showing their potential to reduce phytate content in fiber-rich products for human consumption (15, 16). However, no genetic information about the corresponding enzymes was available.Identification and purification of bifidobacterial phytases. When the genomes from B. pseudocatenulatum ATCC 27919 (GenBank accession no. NZ_ABXX02000003) and B. longum subsp. infantis ATCC 15697 (GenBank accession no. CP001095) were being searched for the presence of genes encoding putative phosphatases, two genes (BIFPSEUDO_03792 and BLON_0263, designated hereinafter PhypA and PhylA, respectively) attracted our attention. These genes encoded two proteins with 59% amino acid identity which possessed histidine acid phosphatase (HAP) domains (PF00328). Furthermore, PhypA and PhylA displayed N-terminal signal peptides for secretion and a predicted C-terminal sortase-dependent cell wall-anchoring domain. Initial characterization of the phytase activity in both bifidobacterial strains revealed that it was mainly located at the cell wall/membrane fractions (data not shown). Hence, the identified genes were good candidates for encoding the bifidobacterial phytases.Sequence analysis additionally showed that the typical HAP signature sequence of the histidine-containing catalytic site (RH GXRXP) was replaced by RHGSRGL in PhypA and PhylA and that the aspartate of the C-terminal HD domain was replaced by alanine. Remarkably, the putative HAP homologues closer to PhylA and PhypA found in databases, belonging to the Actinobacteria, Betaproteobacteria, and Gammaproteobacteria, show the same...

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A Calcium-Activated Phytase from Pollen of Lilium longiflorum

Cited by 59 publications

References 6 publications

Alkaline Phytase Activity in Nonionic Detergent Extracts of Legume Seeds

Alkaline Phytase Activity in Nonionic Detergent Extracts of Legume Seeds

Reduction of phytic acid and enhancement of bioavailable micronutrients in food grains

Novel Phytases from Bifidobacterium pseudocatenulatum ATCC 27919 and Bifidobacterium longum subsp. infantis ATCC 15697

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