Document Detail


Activation of polyphenol oxidase in extracts of bran from several wheat (Triticum aestivum) cultivars using organic solvents, detergents, and chaotropes.
MedLine Citation:
PMID:  11929305     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Polyphenol oxidase (PPO), known to induce browning in wheat-based products, has been shown to be activatable in wheat (Triticum aestivum) bran extracts by chemical compounds. The activity in the extracts could be increased to varying degrees with acetone, methanol, ethanol, 2-propanol, and n-butanol as additives in the extraction buffer. The most potent alcoholic activator was n-butanol (about a 3-fold increase), followed by 2-propanol and ethanol, whereas methanol had the least effect. Ionic detergents in the extraction buffer were also good activators, with sodium dodecyl sulfate (SDS) being more potent (3-fold increase) than cetyltrimethylammonium bromide (CTAB) that had only half as much effect, whereas the nonionic detergent, Triton X-114, was ineffective. The chaotropes, urea and guanidine x HCl (GND), were the most potent activators of all, increasing the activity over 4-fold. Of the two chaotropes, GND was more effective at lower concentrations (<6 M) than urea. However, the enzyme activity lessened at a higher concentration of GND (6 M), while there was a further increase in the activity with 6 M urea treatment. The activity lessened with higher concentration of GND presumably as a result of extensive denaturation of the enzyme, as GND is known to be a more potent denaturant than urea. It is hypothesized that in wheat PPO exists in an inactive form which may be activated by the presence of activators, hitherto unknown, similar in effect to that elicited by the chemical denaturants in this study.
Authors:
Moses Okot-Kotber; Allan Liavoga; Kwon-Joong Yong; Katherine Bagorogoza
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of agricultural and food chemistry     Volume:  50     ISSN:  0021-8561     ISO Abbreviation:  J. Agric. Food Chem.     Publication Date:  2002 Apr 
Date Detail:
Created Date:  2002-04-03     Completed Date:  2002-05-29     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0374755     Medline TA:  J Agric Food Chem     Country:  United States    
Other Details:
Languages:  eng     Pagination:  2410-7     Citation Subset:  IM    
Affiliation:
Department of Grain Science and Industry, Kansas State University, Manhattan, Kansas 66506, USA. bmo@wheat.ksu.edu.
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MeSH Terms
Descriptor/Qualifier:
1-Butanol / pharmacology
2-Propanol / pharmacology
Catechol Oxidase / metabolism*
Detergents / pharmacology*
Enzyme Activation / drug effects
Ethanol / pharmacology
Guanidine / pharmacology*
Plant Extracts / chemistry*
Sodium Dodecyl Sulfate / pharmacology
Solvents
Triticum / enzymology*
Urea / pharmacology*
Chemical
Reg. No./Substance:
0/Detergents; 0/Plant Extracts; 0/Solvents; 113-00-8/Guanidine; 151-21-3/Sodium Dodecyl Sulfate; 57-13-6/Urea; 64-17-5/Ethanol; 67-63-0/2-Propanol; 71-36-3/1-Butanol; EC 1.10.3.1/Catechol Oxidase

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