Chemical analyses of sample, It may be to prevent interference of fat with protein
Dear Sir ( Murwan khalid Sabahelkhier ),
As I think, it is not mandatory defatting of sample before assessing protein content. After all, defatting can be done depending on some special purposes (e.g., to avoid interference of lipid, to measure protein percentage in defatted samples etc.)
Lipids are always interacted with protein extraction and protein measurement, the lipid covers the protein and prevent it from precipitation or from extraction by any type of buffer, and for determination of protein, most of kits that used for protein determination overlap with presence of lipids, there is why it is highly recommended to defat any samples before going to protein assay or protein extraction,
Thank you A. M. Kamel. We usually measures protein by Kjeldahl apparatus from marine resources, most of the time without deoiling. Could you please give me idea, how much interference of result in this case?
Monjurul Haq and Murwan khalid Sabahelkhier
Depends on the percentage of lipids in the samples, but with Kjeldahl, the case will change because this type of extraction depends on the digestion of protein for quantitative determination of nitrogen contained in organic substances plus the nitrogen in inorganic ammonia and ammonium, even in this case, the percentage of digestion will decrease by increasing the oils and fat content in the samples, (not less than 10%), what I strongly mean is the advanced method that depends on the extraction of protein without digestion like extraction by precipitation or extraction with buffer, then it is highly recommended to defat the samples as I mentioned before,
I hope that I could help you for the explanation
Regards
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