When performing gel-electrophoresis we always use agarose. Is there a reason we can't perform it using Agar?

And in microbial culture Agar is commonly used as solidifying agent, could this be replaced with agarose.

I understand the difference in price, composition, and manufacturing but other than that how would it affect the result?

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    – bob1
    Feb 25 at 19:12

1 Answer 1


Agarose is indeed more expensive than agar because it is purified from agar, i.e. it is agar minus the agaropectin. Agaropectin is heterogeneous, and modified with acidic side-groups. The consequence of this is that it would interfere with the migration of nucleic acid in the gel. Similarly, agarose is sometimes used for observing zones of inhibitions of growth or lysis plages of microorganisms caused some antimicrobials, because it interferes less with their diffusion than agar.


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