Dear Serge,

your question is very , very "vague".

- At first please define the SOURCE of your myoglobin (you know that MYOGLOBIN is a globular HEME protein and localized in red muscle fibers).

- What a kind of spectrometer are you using (single , dual beam or arrays)?

- You must isolate and purify your myoglobin prior to measure via UV-Vis

- Tabulated spectral data is depending of your myoglobin e.g of oxymyoglobin source and the solvent used for measurements.

If you use 50 mM phosphate buffer at pH 7.0, your spectrum will give a good record between 650 to 750 nm. ( cut off of the buffer solution must be considered)

Please rewrite e.g. modify your question with more infos for a good answer.

A research gate member published this article:

Characterisation of myoglobin from sardine (Sardinella gibbosa) dark muscle

Manat Chaijan, Soottawat Benjakul, Wonnop Visessanguan, Cameron Faustman

Department of Food Technology, Faculty of Agro-Industry, Prince of Songkla University, Hat Yai, Songkla 90112, Thailand; National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, 113 Phaholyothin Road, Klong 1, Klong Luang, Pathumthani 12120, Thailand; Department of Animal Science, University of Connecticut, 3636 Horsebarn Road Ext., Storrs, CT 06269-4040, USA

Food Chemistry 01/2007; DOI:10.1016/j.foodchem.2005.09.030

ABSTRACT Myoglobin from the dark muscle of sardine (Sardinella gibbosa) with the molecular weight of 15.3 kDa was isolated and characterised. The different myoglobin derivatives exhibited varying thermal unfolding characteristics. Deoxymyoglobin showed

please read it!!

Good luck

JRG

-

Dear Jean,

Thanks for the info! I'd like to get either mua of some known concentration or the molar extinction coefficients (this would be ideal) for a direct side-by-side comparison with those of Hb and HbO2. There is a good source of tabulated optical data for Hb and HbO2 at http://omlc.ogi.edu/spectra/hemoglobin/index.html so I hoped that there would be similar data sets for Mb and MbO2 in water. Sorry for the confusion!

Regards,

Serge

Dear Serge,

thank you for fast answer but there isin my answer no confusion

I clicked your link but it is a "slight shoddy" link . WHY??

- the author gives some details as follows:

xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

Tabulated Molar Extinction Coefficient for Hemoglobin in Water

These values for the molar extinction coefficient e in [cm-1/(moles/liter)] were compiled by Scott Prahl using data from

W. B. Gratzer, Med. Res. Council Labs, Holly Hill, London

N. Kollias, Wellman Laboratories, Harvard Medical School, Boston

To convert this data to absorbance A, multiply by the molar concentration and the pathlength. For example, if x is the number of grams per liter and a 1 cm cuvette is being used, then the absorbance is given by

(e) [(1/cm)/(moles/liter)] (x) [g/liter] (1) [cm]

A = ---------------------------------------------------

64,500 [g/mole]

using 64,500 as the gram molecular weight of hemoglobin.

To convert this data to absorption coefficient in (cm-1), multiply by the molar concentration and 2.303,

µa = (2.303) e (x g/liter)/(64,500 g Hb/mole)

where x is the number of grams per liter. A typical value of x for whole blood is x=150 g Hb/liter.

xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

but there is no details about the quality of water (bidist. water p.e.) and the 1 cm cuvette is without quality and kind of cuvette (p.e. quartz, glass ....) and cut off of water.

No infos about the used spectrometer (single , dual or arrays). Very important !

- No infos about the purity of hemoglobin (and its kind) and about the analysis prior to weight for the wished concentration. The presence of impurities or water will give a wrong concentration e.g. A and later e (epsilon)

- If you find such tabulated data for myoglobin and derivative(s), please control the source and quality and infos about purity.

- Please note that most investiagationsabout myoglobin and der. were done in buffer in the past.

you cannot compare values in water and in buffer either for hemo or myoglobin.

Good luck

JRG

Hi Serge,

There is a sort of a "bible" of myoglobin and hemoglobin in where you will find extinction coefficients and all sorts of other data on both proteins.

Best Signe

http://www.sciencemag.org/content/178/4058/296.citation

Dear Serge Grabtchak,

I have the same question.

Please answer, did you find a source of tabulated spectral data of absorption coefficients for myoglobin and oxy-myoglobin?

I need this data to calculate SmO2.

Thank you, hope to your answer. 

Best regards, 

Dmitriy.