Chemical Forums
Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: Victor66 on August 17, 2015, 01:59:29 AM
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Hello!
What does "FIP-U/g DM" mean? As far as I can tell, DM could be dry matter, which makes sense in the context, but what are the other terms?
It's related to pepsine and its use in an experiment, it says "80 FIP-U/g DM), DM being the dried organic matter pepsine is used on.
Also, where can I read the protocol for the carbazole method?
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Well I managed to find this!
http://www.usp.org/sites/default/files/usp_pdf/EN/meetings/workshops/langdon.pdf (http://www.usp.org/sites/default/files/usp_pdf/EN/meetings/workshops/langdon.pdf)
See where this gets you.
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U often stands for units of enzyme. Units are an extensive property that measures the activity of an enzyme. Related to it is specific activity, an intensive property that is usually measured in U/mg. The specific activity should be the same for various preparations of an enzyme that is both pure and completely active.
There is a generally accepted definition of units, which is that one unit of an enzyme is that amount of enzyme that produces a rate of 1 micromole of substrate to product per minute under specified conditions of temperature, pH, etc. “One USP Unit of Pepsin activity is the activity that releases the equivalent of 1 μmole of tyrosine per minute under conditions of the Assay." (also from the powerpoint).
However, some enzymes have a special definition of unit. The powerpoint that discodermolide found talks about the international pharmaceutical federation (FIP) and "European units," but the latter term is not familiar to me. The powerpoint is pretty good at illustrating the problem of multiple definitions of units.
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Thank you, now I understand what it means.