[diablo]

[sjb]

Do you have a conversion between "units" and mass?

Trouble is, in my experience biochemical "units" could be anything, from moles to activities to ...

S

[Yggdrasil]

In general, there is no conversion to do so.  You'd be better off directly measuring the concentration of the protein (e.g. by looking at the absorption at 280nm or using a colorimetric assay like the Bradford assay).  Note that for most of these assays to work, you need a reasonably pure sample.  If you have bought your protein from a company, never assume it is pure.  You can check the purity by a method such as SDS-PAGE.

[diablo]

ok, thx for your answer !

[JGK]

You can do it if you can find a literature value for Units/mg for your enzyme.

[Yggdrasil]

You can do it if you can find a literature value for Units/mg for your enzyme.

You'd have to be careful here as the value for units/mg is highly dependent on factors like temperature and buffer conditions.