Copper containing enzyme Laccase unit is based on spectrometric data. How to measure 1 unit laccase for the experimental use. Any reference?
Hello Aniruddha, the unit is still the same umol/min (U)/mL. Please see: https://www.sigmaaldrich.com/technical-documents/protocols/biology/enzymatic-assay-of-laccase.html.
Thanks Dr. Ekpenyong for your effort. I think the link is trully helpful.
Regards
Aniruddha
What is the Unit of enzyme Laccase?
I send you one protocol to test laccase activity thatwas described in the publication:
Characterization of Yellow bacterial laccase SmLac / role of redox mediators in azo dye decolorization.
Galai Said; Korri-Youssoufi Hafsa and Marzouki M. Nejib (2014)
Journal of Chemical Technology & Biotechnology Vol 89, Issue 11, pages 1741–1750
Laccase activity measurement
Laccase activity was measured following the oxidation of two substrates: 2,6 dimethoxyphenol (DMP) and 2,2_-azino-bis(3- ethylbenzthiazoline-6-sulfonic acid) (ABTS). DMP oxidase activity (DMPO) was monitored at 468nm as the production of 3,3_,5,5_- tetramethoxydiphenylquinone (_468 =14.800 mol L-1 cm-1). The oxidation reaction took place in the presence of 2 mmol L-1 DMP in 0.1 mol l-1 phosphate buffer pH 5.0 and 0.2 mmol L-1 CuSO4. ABTS oxidase activity (ABTSO) was measured by monitoring its oxidation at 420nm (_420 =36.000 mol L-1 cm-1). The reaction mixture contained 0.5 mmol L-1 ABTS and 0.2 mmol L-1 CuSO4 in 0.1 mol L-1 phosphate buffer pH 5.0. One unit of enzyme activity (U) was defined as the amount of enzyme that catalyzed the appearance of 1 μmol of product per minute at 40 ◦C.
Thank you Professor Nejib Marzouki for your article. Let me check it for detailed of defining of laccase unit for the experiment.
Sincerely,
Aniruddha
Hi dear colleague As researchers have explained the laccase as enzymes to the end, its activity is also defined as the amount of enzyme that catalyzes the conversion of 1 μmol of substrate in one minute. The specific activity as the number of units of enzyme per milligram of protein (U / mg prot) or per milliliter of solution (U / ml). In the specific case of laccases, these enzyme have a great potential for degradation of different compounds, so the determination of the enzymatic activity of these multicobre oxidases are quantified mostly by UV / Vis spectroscopy. Because there is a colorimetric reaction derived from the oxidation of a substrate of low redox potential, for example: ABTS (2,2'-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid), Guaiacol (O-methoxyphenol), Tyrosine 2-Amino-3- (4-hydroxyphenyl) -propanoic acid, Hydroquinone (1,4-dihydroxybenzene) and syringaldazine (4-hydroxy-3,5-dimethoxybenzaldehyde azine). So depending on the test you use may have some variation but generally a unit of enzymatic activity (U) will be the amount of bio transformed substrate or formed product per ml of enzyme.
Thanks Maryen Alberto for your lucid explanation with the justification of enzymatic acitivity unit (U). Now I got it.
Sincerely,
Aniruddha Sarker
Hi Aniruddha Sarker, wishing success to you dear friend, I hope the following article will help to you.
Thank You dear fellow scientist Bahman Khoshru for your nice effort in this regard.
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