| Purification and characterization of polyphenol oxidase from nettle (Urtica dioica L.) and inhibitory effects of some chemicals on enzyme activity. | |
MedLine Citation:
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PMID: 16119202 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Polyphenol oxidase (PPO) of nettle (Urtica dioica L.) was extracted and purified through (NH4)2SO4 precipitation, dialysis, and CM-Sephadex ion-exchange chromatography and was used for its characterization. The PPO showed activity to catechol, 4-methylcatechol, L-3,4-dihydroxyphenylalanine (L-DOPA), L-tyrosine, p-cresol, pyrogallol, catechin and trans-cinnamic acid. For each of these eight substrates, optimum conditions such as pH and temperature were determined and L-tyrosine was found to be one of the most suitable substrates. Optimum pH and temperature were found at pH 4.5 and 30 degrees C respectively and Km and Vmax values were 7.90 x 10(-4) M, and 11290 EU/mL for with L-tyrosine as substrate. The inhibitory effect of several inhibitors, L-cysteine chloride, sodium azide, sodium cyanide, benzoic acid, salicylic acid, L-ascorbic acid, glutathione, thiourea, sodium diethyl dithiocarbamate, beta-mercaptoethanol and sodium metabisulfite were tested. The most effective was found to be sodium diethyl dithiocarbamate which acted as a competitive inhibitor with a Ki value of 1.79 x 10(-9)M. In addition one isoenzyme of PPO was detected by native polacrylamide slab gel electrophoresis. |
Authors:
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Ilhami Güllçin; O Irfan Küfrevioğlu; Münir Oktay |
Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: Journal of enzyme inhibition and medicinal chemistry Volume: 20 ISSN: 1475-6366 ISO Abbreviation: J Enzyme Inhib Med Chem Publication Date: 2005 Jun |
Date Detail:
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Created Date: 2005-08-25 Completed Date: 2005-12-02 Revised Date: 2007-03-21 |
Medline Journal Info:
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Nlm Unique ID: 101150203 Medline TA: J Enzyme Inhib Med Chem Country: England |
Other Details:
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Languages: eng Pagination: 297-302 Citation Subset: IM |
Affiliation:
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Atatürk University, Faculty of Science and Arts, Department of Chemistry, 25240, Erzurum, Turkey. |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Ascorbic Acid
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pharmacology Catechol Oxidase / antagonists & inhibitors, isolation & purification*, metabolism, pharmacology Dithioerythritol / pharmacology Ditiocarb / pharmacology Enzyme Inhibitors / metabolism, pharmacology Enzyme Stability Glutathione / pharmacology Hydrogen-Ion Concentration Kinetics Potassium Cyanide / pharmacology Sodium Azide / pharmacology Substrate Specificity Sulfites / pharmacology Temperature Thiourea / pharmacology Urtica dioica / chemistry, enzymology* |
| Chemical | |
Reg. No./Substance:
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0/Enzyme Inhibitors; 0/Sulfites; 147-84-2/Ditiocarb; 151-50-8/Potassium Cyanide; 26628-22-8/Sodium Azide; 50-81-7/Ascorbic Acid; 62-56-6/Thiourea; 6892-68-8/Dithioerythritol; 70-18-8/Glutathione; 7681-57-4/sodium metabisulfite; EC 1.10.3.1/Catechol Oxidase |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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