One thing that I didn't understand was how katals are to be measured / quantified. Say I did a Friedel Crafts and know my gmol / sec or gmol / ( gm.Catalyst sec) etc. how do I convert that into katals.
Unfortunately wikipedia wasn't very clear on it.
"One katal of trypsin, for example, is that amount of trypsin which breaks a mole of peptide bonds per second under specified conditions." So a katal is expressed in moles per second. From the Wikipedia entry on enzyme units (an older way of expressing activity): "1 U = 1/60 micro katal = 16.67 nano katal." One reason why moles per second and µmol per minute were chosen and not a unit of concentration per unit time was to take the volume of the assay out of the math.
Units or katals are extensive quantities, and they are helpful in tracking the course of an enzyme purification. You can often buy enzymes in terms of how many units of enzyme are present, such as 5000 units of pyruvate kinase. Specific activity (units/mg protein) tell one a bit more about the purity and quality of an enzyme.