scholarly journals Purification and characterization of polyphenol oxidase from nettle (Urtica dioicaL.) and inhibitory effects of some chemicals on enzyme activity

2005 ◽  
Vol 20 (3) ◽  
pp. 297-302 ◽  
Author(s):  
İlhamİ Gülçİn ◽  
Ö. İrfan Küfrevİoğlu ◽  
Münİr Oktay
Keyword(s):  
Enzyme Activity ◽  
Polyphenol Oxidase ◽  
Inhibitory Effects ◽  
Purification And Characterization

scholarly journals Study on Purification and Characterization of Polyphenol Oxidase from Acetes chinensis

Molecules ◽  
2021 ◽  
Vol 26 (24) ◽  
pp. 7545
Author(s):  
Jianyou Zhang ◽  
Guangcheng Zhou ◽  
Lifeng Fei ◽  
Lifan Chen ◽  
Lei Sun ◽  
...  
Keyword(s):  
Polyphenol Oxidase ◽  
Biochemical Characterization ◽  
Specific Activity ◽  
Deae Cellulose ◽  
Enzymatic Reactions ◽  
Inhibitory Effects ◽  
Purification And Characterization ◽  
Effective Prevention ◽  
Ammonium Sulphate Precipitation

Acetes chinensis (belonging to the Decapoda Sergestidae genus) is widely distributed in East Asian waters and is extremely widespread and present in the shallow coastal areas of China. Polyphenol oxidase (PPO), which was extracted from Acetes chinensis, was purified in a four-step procedure involving phosphate-buffered saline treatment, ammonium sulphate precipitation, DEAE-Cellulose chromatography, and Phenyl-Sepharose HP chromatography, and then, its biochemical characterization was measured. The specific activity of the purified enzyme was increased to 643.4 U/mg, which is a 30.35 times increase in purification, and the recovery rate was 17.9%. L-dopa was used as the substrate, the enzymatic reactions catalyzed by PPO conformed to the Michaelis equation, the maximum reaction velocity was 769.23 U/mL, and the Michaelis constant Km was 0.846 mmol/L. The optimal pH of PPO from Acetes chinensis was 7.5, and the optimal temperature was 35 °C. The metal ions experiment showed that Mn2+ and K+ could enhance the activity of PPO; that Ba2+ and Ca2+ could inhibit the activity of PPO; and that Cu2+ had a double effect on PPO, increasing the PPO activity at low concentrations and inhibiting the PPO activity at high concentrations. The inhibitor experiment showed that the inhibitory effects of EDTA and kojic acid were weak and that ascorbic acid and sodium pyrophosphate had good inhibitory effects. The purification and characterization of Acetes chinensis serve as guidelines for the prediction of enzyme behavior, leading to effective prevention of enzymatic browning during processing.

scholarly journals Partial purification and characterization of an endo-α-N-acetylgalactosaminidase from the culture medium of Streptomyces sp. OH-11242

1992 ◽  
Vol 288 (2) ◽  
pp. 475-482 ◽  
Author(s):  
I Ishii-Karakasa ◽  
H Iwase ◽  
K Hotta ◽  
Y Tanaka ◽  
S Omura
Keyword(s):  
Enzyme Activity ◽  
Culture Medium ◽  
Gel Filtration ◽  
Partial Purification ◽  
Gastric Mucus ◽  
Purification And Characterization ◽  
Streptomyces Sp ◽  
Optimum Ph ◽  
New Type

For the purification of a new type of endo-alpha-N-acetylgalactosaminidase from the culture medium of Streptomyces sp. OH-11242 (endo-GalNAc-ase-S) [Iwase, Ishii, Ishihara, Tanaka, Omura & Hotta (1988) Biochem. Biophys. Res. Commun. 151, 422-428], a method for assaying enzyme activity was established. Using purified pig gastric mucus glycoprotein (PGM) as the substrate, oligosaccharides liberated from PGM were pyridylaminated, and the reducing terminal sugars of oligosaccharides larger than Gal beta 1-3GalNAc were analysed by h.p.1.c. The crude enzyme of endo-GalNAc-ase-S was prepared as an 80% (w/v) ammonium sulphate precipitate from the concentrated culture medium. The enzyme was partially purified by gel chromatofocusing and subsequent DEAE-Toyopearl chromatography. Endo-enzyme activity eluted around pI 4.8 on a gel chromatofocusing column and eluted with 0.19-0.25 M-NaCl on a DEAE-Toyopearl column. In the enzyme fraction obtained, no exo-glycosidases or proteases could be detected. The molecular mass of the enzyme was estimated as 105 kDa by gel filtration, and the optimum pH was 5.5. Endo-GalNAc-ase-S hydrolysed the O-glycosidic linkage between GalNAc and Ser (Thr) in 3H-labelled and unlabelled asialofetuin, liberating both the disaccharide (Gal beta 1-3GalNAc) and the tetrasaccharide [Gal beta 1-3 (Gal beta 1-4GlcNAc beta 1-6)GalNAc]. When endo-alpha-N-acetylgalactosaminidase from Alcaligenes sp. (endo-GalNac-ase-A) was incubated with 3H-labelled and unlabelled asialofetuin, only the disaccharide (Gal beta 1-3GalNAc) was liberated.

Purification and characterization of carbonic anhydrase from sheep kidney and effects of sulfonamides on enzyme activity

2013 ◽  
Vol 21 (6) ◽  
pp. 1522-1525 ◽  
Author(s):  
Ramazan Demirdağ ◽  
Veysel Çomaklı ◽  
Murat Şentürk ◽  
Deniz Ekinci ◽  
Ö. İrfan Küfrevioğlu ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
Carbonic Anhydrase ◽  
Purification And Characterization

Purification and Characterization of Dog-rose (RosadumalisRechst.) Polyphenol Oxidase

1996 ◽  
Vol 44 (10) ◽  
pp. 2982-2986 ◽  
Author(s):  
Halis Şakiroǧlu ◽  
Ömer I. Küfrevioǧlu ◽  
Ismail Kocaçalişkan ◽  
Münir Oktay ◽  
Yavuz Onganer
Keyword(s):  
Polyphenol Oxidase ◽  
Purification And Characterization ◽  
Dog Rose
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