| Isolation and partial characterisation of acid phosphatase isozymes from dormant oilseed of Corylus avellana L. | |
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MedLine Citation:
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PMID: 15048567 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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The acid phosphatase (orthophosphoric-monoester phosphohydrolase, EC 3.1.3.2) complement from dormant hazel (Corylus avellana L.) seeds was found to exhibit significant electrophoretic heterogeneity partially attributable to the presence of distinct molecular forms. In axiferous tissue, total acid phosphatase activity increased in a biphasic fashion during chilling, a treatment necessary to alleviate seed dormancy. Three acid phosphatase isozymes were isolated from cotyledons of dormant hazel seeds by successive ammonium sulphate precipitation, size-exclusion, Concanavalin A affinity, cation- and anion-exchange chromatographies resulting in 75-, 389- and 191-fold purification (APase1, APase2, APase3, respectively). The three glycosylated isoforms were isolated to catalytic homogeneity as determined by electrophoretic, kinetic and heat-inactivation studies. The native acid phosphatase complement of hazel seeds had an apparent Mr of 81.5 +/- 3.5 kDa as estimated by size-exclusion chromatography, while the determined pI values were 5.1 (APase1), 6.9 (APase2) and 7.3 (APase3). The optimum pH for p-nitrophenyl phosphate hydrolysis was pH 3 (APase1), pH 5.6 (APase2) and pH 6 (APase3). The hazel isozymes hydrolysed a variety of phosphorylated substrates in a non-specific manner, exhibiting low Km and the highest specificity constant (Vmax/ Km) for pyrophosphate. They were not primary phytases since they could not initiate phytic acid hydrolysis, while APase2 and APase3 had significant phospho-tyrosine phosphatase activity. Inorganic phosphate was a competitive inhibitor, while activity was significantly impaired in the presence of vanadate and fluoride. |
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Authors:
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Vasilios M E Andriotis; James D Ross |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't Date: 2004-03-27 |
Journal Detail:
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Title: Planta Volume: 219 ISSN: 0032-0935 ISO Abbreviation: Planta Publication Date: 2004 Jun |
Date Detail:
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Created Date: 2004-06-01 Completed Date: 2004-08-31 Revised Date: 2006-11-15 |
Medline Journal Info:
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Nlm Unique ID: 1250576 Medline TA: Planta Country: Germany |
Other Details:
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Languages: eng Pagination: 346-58 Citation Subset: IM |
Copyright Information:
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Copyright 2004 Springer-Verlag |
Affiliation:
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School of Plant Sciences, The University of Reading, Whiteknights, Reading, RG6 6AS, UK. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Acid Phosphatase
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chemistry*,
metabolism Chromatography, Affinity Corylus / enzymology* Germination Hydrogen-Ion Concentration Isoenzymes / metabolism Kinetics Molecular Weight Plant Proteins / metabolism Seeds / enzymology, growth & development Substrate Specificity |
| Chemical | |
Reg. No./Substance:
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0/Isoenzymes; 0/Plant Proteins; EC 3.1.3.2/Acid Phosphatase |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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