Asian Science Citation Index is committed to provide an authoritative, trusted and significant information by the coverage of the most important and influential journals to meet the needs of the global scientific community.  
ASCI Database
308-Lasani Town,
Sargodha Road,
Faisalabad, Pakistan
Fax: +92-41-8815544
Contact Via Web
Suggest a Journal
International Journal of Food Properties
Year: 2011  |  Volume: 14  |  Issue: 4  |  Page No.: 809 - 821

Comparison of Polyphenol Oxidases Prepared From Different Parts of Artichoke (Cynara Scolymus L.)

Didem Tuncay and Hulya Yagar    

Abstract: Artichoke polyphenol oxidases (PPOs) were obtained by (NH4)2SO4 precipitation using ascorbic acid, polyvinylpyrrolidone, and Triton X-100. The PPO content of artichoke head (AHPPO) was 8820 units (mg protein)−1 as compared with 3370 units (mg protein)−1 in artichoke leaves-and-stem (ALSPPO) by using catechol as a substrate. The substrates of both AHPPO and ALSPPO are o-diphenols, such as catechol, pyrogallol, and L-DOPA. Optimum pH and temperature of both PPOs were determined. AHPPO had higher thermal stability than ALSPPO. Also, Tm (the midpoint of thermal inactivation) and t1/2 (half-life) values were determined. Km and Vmax of both PPOs were observed to be similar. Twelve inhibitors were tested and their I50 values were determined. The most effective inhibitors were found to be potassium cyanide, ascorbic acid, L-cysteine, and thiourea. Sodiumdodecylsulfate, urea, and cupric sulfate caused an increase about 20–30% in the PPO activity.

View Fulltext    |   Related Articles   |   Back
 
 
   
 
 
 
  Related Articles

 
 
 
 
Copyright   |   Desclaimer   |    Privacy Policy   |   Browsers   |   Accessibility