File Download

There are no files associated with this item.

  Links for fulltext
     (May Require Subscription)
Supplementary

Article: Phytase activity in tobacco (Nicotiana tabacum) root exudates is exhibited by a purple acid phosphatase

TitlePhytase activity in tobacco (Nicotiana tabacum) root exudates is exhibited by a purple acid phosphatase
Authors
KeywordsNicotiana tabacum
Phosphorus
Phytase
Phytate
Purple acid phosphatase
Root exudates
Solanaceae
Tobacco
Issue Date2008
PublisherPergamon. The Journal's web site is located at http://www.elsevier.com/locate/phytochem
Citation
Phytochemistry, 2008, v. 69 n. 2, p. 365-373 How to Cite?
AbstractPhytases are enzymes that catalyze liberation of inorganic phosphates from phytate, the major organic phosphorus in soil. Tobacco (Nicotiana tabacum) responds to phosphorus starvation with an increase in extracellular phytase activity. By a three-step purification scheme, a phosphatase with phytase activity was purified 486-fold from tobacco root exudates to a specific activity of 6,028 nkat mg -1 and an overall yield of 3%. SDS-PAGE revealed a single polypeptide of 64 kDa, thus indicating apparent homogeneity of the final enzyme preparation. Gel filtration chromatography suggested that the enzyme was a ca. 56 kDa monomeric protein. De novo sequencing by tandem mass spectrometry resulted in a tryptic peptide sequence that shares high homology with several plant purple acid phosphatases. The identity of the enzyme was further confirmed by molybdate-inhibition assay and cDNA cloning. The purified enzyme exhibited pH and temperature optima at 5.0-5.5 and 45 °C, respectively, and were found to have high affinities for both p-nitrophenyl phosphate (pNPP; K m = 13.9 μM) and phytate (K m = 14.7 μM), but a higher kcat for pNPP (2,056 s -1) than phytate (908 s -1). Although a broad specificity of the enzyme was observed for a range of physiological substrates in soil, maximum activity was achieved using mononucleotides as substrates. We conclude that the phytase activity in tobacco root exudates is exhibited by a purple acid phosphatase and its catalytic properties are pertinent to its role in mobilizing organic P in soil. © 2007 Elsevier Ltd. All rights reserved.
Persistent Identifierhttp://hdl.handle.net/10722/171361
ISSN
2015 Impact Factor: 2.779
2015 SCImago Journal Rankings: 0.935
ISI Accession Number ID
References

 

DC FieldValueLanguage
dc.contributor.authorLung, SCen_HK
dc.contributor.authorLeung, Aen_HK
dc.contributor.authorKuang, Ren_HK
dc.contributor.authorWang, Yen_HK
dc.contributor.authorLeung, Pen_HK
dc.contributor.authorLim, BLen_HK
dc.date.accessioned2012-10-30T06:13:37Z-
dc.date.available2012-10-30T06:13:37Z-
dc.date.issued2008en_HK
dc.identifier.citationPhytochemistry, 2008, v. 69 n. 2, p. 365-373en_HK
dc.identifier.issn0031-9422en_HK
dc.identifier.urihttp://hdl.handle.net/10722/171361-
dc.description.abstractPhytases are enzymes that catalyze liberation of inorganic phosphates from phytate, the major organic phosphorus in soil. Tobacco (Nicotiana tabacum) responds to phosphorus starvation with an increase in extracellular phytase activity. By a three-step purification scheme, a phosphatase with phytase activity was purified 486-fold from tobacco root exudates to a specific activity of 6,028 nkat mg -1 and an overall yield of 3%. SDS-PAGE revealed a single polypeptide of 64 kDa, thus indicating apparent homogeneity of the final enzyme preparation. Gel filtration chromatography suggested that the enzyme was a ca. 56 kDa monomeric protein. De novo sequencing by tandem mass spectrometry resulted in a tryptic peptide sequence that shares high homology with several plant purple acid phosphatases. The identity of the enzyme was further confirmed by molybdate-inhibition assay and cDNA cloning. The purified enzyme exhibited pH and temperature optima at 5.0-5.5 and 45 °C, respectively, and were found to have high affinities for both p-nitrophenyl phosphate (pNPP; K m = 13.9 μM) and phytate (K m = 14.7 μM), but a higher kcat for pNPP (2,056 s -1) than phytate (908 s -1). Although a broad specificity of the enzyme was observed for a range of physiological substrates in soil, maximum activity was achieved using mononucleotides as substrates. We conclude that the phytase activity in tobacco root exudates is exhibited by a purple acid phosphatase and its catalytic properties are pertinent to its role in mobilizing organic P in soil. © 2007 Elsevier Ltd. All rights reserved.en_HK
dc.languageengen_US
dc.publisherPergamon. The Journal's web site is located at http://www.elsevier.com/locate/phytochemen_HK
dc.relation.ispartofPhytochemistryen_HK
dc.subjectNicotiana tabacumen_HK
dc.subjectPhosphorusen_HK
dc.subjectPhytaseen_HK
dc.subjectPhytateen_HK
dc.subjectPurple acid phosphataseen_HK
dc.subjectRoot exudatesen_HK
dc.subjectSolanaceaeen_HK
dc.subjectTobaccoen_HK
dc.subject.mesh6-Phytase - Chemistry - Metabolismen_US
dc.subject.meshAcid Phosphatase - Chemistry - Isolation & Purification - Metabolism - Secretionen_US
dc.subject.meshCatalysisen_US
dc.subject.meshConserved Sequenceen_US
dc.subject.meshDna, Complementary - Geneticsen_US
dc.subject.meshEnzyme Activation - Drug Effectsen_US
dc.subject.meshGlycoproteins - Chemistry - Isolation & Purification - Metabolism - Secretionen_US
dc.subject.meshKineticsen_US
dc.subject.meshMolecular Sequence Dataen_US
dc.subject.meshMolecular Structureen_US
dc.subject.meshMolybdenum - Pharmacologyen_US
dc.subject.meshPhylogenyen_US
dc.subject.meshPlant Roots - Enzymologyen_US
dc.subject.meshSequence Alignmenten_US
dc.subject.meshSoilen_US
dc.subject.meshSubstrate Specificityen_US
dc.subject.meshTobacco - Enzymologyen_US
dc.titlePhytase activity in tobacco (Nicotiana tabacum) root exudates is exhibited by a purple acid phosphataseen_HK
dc.typeArticleen_HK
dc.identifier.emailWang, Y: yuwanghk@hku.hken_HK
dc.identifier.emailLim, BL: bllim@hkucc.hku.hken_HK
dc.identifier.authorityWang, Y=rp00239en_HK
dc.identifier.authorityLim, BL=rp00744en_HK
dc.description.naturelink_to_subscribed_fulltexten_US
dc.identifier.doi10.1016/j.phytochem.2007.06.036en_HK
dc.identifier.pmid17897689-
dc.identifier.scopuseid_2-s2.0-37549071437en_HK
dc.identifier.hkuros149508-
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-37549071437&selection=ref&src=s&origin=recordpageen_HK
dc.identifier.volume69en_HK
dc.identifier.issue2en_HK
dc.identifier.spage365en_HK
dc.identifier.epage373en_HK
dc.identifier.isiWOS:000253267300007-
dc.publisher.placeUnited Kingdomen_HK
dc.identifier.scopusauthoridLung, SC=8619522500en_HK
dc.identifier.scopusauthoridLeung, A=7403012653en_HK
dc.identifier.scopusauthoridKuang, R=23100196200en_HK
dc.identifier.scopusauthoridWang, Y=34973733700en_HK
dc.identifier.scopusauthoridLeung, P=35740926800en_HK
dc.identifier.scopusauthoridLim, BL=7201983917en_HK

Export via OAI-PMH Interface in XML Formats


OR


Export to Other Non-XML Formats