Polyphenol oxidase from sweet potato: purification and properties

1992 ◽  
Vol 40 (12) ◽  
pp. 2369-2373 ◽  
Author(s):  
Euclides J. Lourenco ◽  
Valdir A. Neves ◽  
Maraiza A. Da Silva
Keyword(s):  
Sweet Potato ◽  
Polyphenol Oxidase ◽  
Purification And Properties

scholarly journals POLYPHENOL OXIDASE AND PEROXIDASE ENZYME ASSAYS IN SWEET POTATO CULTIVARS HARVESTED AT DIFFERENT TIMES

2019 ◽  
Vol 32 (2) ◽  
pp. 537-542
Author(s):  
SAMARA LOPES DE ALMEIDA ◽  
MARIA APARECIDA DOS SANTOS MORAIS ◽  
JOSÉ RICARDO TAVARES DE ALBUQUERQUE ◽  
AURÉLIO PAES BARROS JÚNIOR ◽  
ADRIANO DO NASCIMENTO SIMÕES ◽  
...  
Keyword(s):  
Sweet Potato ◽  
Polyphenol Oxidase ◽  
Phosphate Buffer ◽  
Reaction Times ◽  
Reaction Medium ◽  
Potato Cultivars ◽  
Enzyme Assays ◽  
Minimal Processing ◽  
Continuous Increase ◽  
Peroxidase Enzyme

ABSTRACT Enzyme assays are based on methodologies described in the literature. However, the enzyme kinetics must be adjusted to obtain more reliable results. This study aimed to adjust assays by testing different polyphenol oxidase (PPO) and peroxidase (POD) extract amounts and reaction times in sweet potato cultivars harvested at different times. Sweet potato cultivars Paraná, Mãe de Família, and ESAM1 were harvested at 120, 150, and 180 days after planting and minimally processed. A 0.25 g sample was used to determine PPO and POD activities immediately after minimal processing at each harvest. Extraction was performed in 1500 μL phosphate buffer (0.2 M, pH 6.0). The PPO assay was performed by adding 10-50 μL extract, 1490-1450 μL phosphate buffer (0.2 M, pH 6.0), and 1500 μL catechol (0.2 M). The POD assay was carried out by adding 10-50 μL extract to a reaction medium containing 1790-1750 μL phosphate buffer (0.2 M, pH 6), 100 μl guaiacol (5 g L-1), and 100 μL hydrogen peroxide (0.8 g L-1). In both cases, the evaluated reaction times were 1, 2, and 3 min. In the three cultivars, PPO and POD activities increased with the volume of extract and reaction time at all harvest times. The enzyme extract volume of 10 μL for 2 min promoted a continuous increase in PPO and POD enzyme activities in all studied cultivars and at all reaction times.

Study on the Process of the Reaction Catalyzed by Polyphenol Oxidase from Purple Sweet Potato

2014 ◽  
Vol 898 ◽  
pp. 153-156 ◽  
Author(s):  
Lu Gao ◽  
Li Chun Zhao ◽  
Ji Dong Duan ◽  
Yan Li Tao
Keyword(s):  
Sweet Potato ◽  
Polyphenol Oxidase ◽  
Substrate Concentration ◽  
Phosphate Buffer ◽  
Phosphate Buffer Solution ◽  
Enzyme Concentration ◽  
Buffer Solution ◽  
Purple Sweet Potato ◽  
The Relationship ◽  
Substrate Concentrations

The polyphenol oxidase (PPO) was extracted from fresh purple sweet potato (PSP) by phosphate buffer solution, and spectrophotometry method was applied in the experiment. The process of the reaction catalyzed by PPO with different substrate concentrations and the relationship between enzyme concentrations and PPO activity were mainly studied here. The result showed that the effect of enzyme concentration on PPO activity was stronger than that of substrate concentration on PPO activity.

scholarly journals Effect of Superheated Steam and Hot Water Spray Treatment on Polyphenol Oxidase Activity in Sweet Potato Leaves

2016 ◽  
Vol 63 (2) ◽  
pp. 86-92
Author(s):  
Kazunori Sasaki ◽  
Itaru Sotome ◽  
Hiroshi Okadome ◽  
Yumi Kai ◽  
Tomoyuki Oki ◽  
...  
Keyword(s):  
Sweet Potato ◽  
Polyphenol Oxidase ◽  
Oxidase Activity ◽  
Superheated Steam ◽  
Hot Water ◽  
Water Spray ◽  
Polyphenol Oxidase Activity ◽  
Sweet Potato Leaves ◽  
Spray Treatment
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