In article <3j3njg$7ud at nrcnet0.nrc.ca>, James.Fethiere at BRI.NRC.CA (James Fethiere) says:
>>Hello all, I am using different endo and exoglycosidases from
>Boeringher to deglycosylate glycoproteins. I usually put an excess
>of enzyme but I would like to know if the is specific amounts of these
>enzymes to use. What i need is a number referring to mg enz/mg of glycoprotein.
>Or in some cases U enz./mg protein, although this unit thing is sometime
This is a very difficult question to give a precise response to. The
number of mg enz/mg substrate and the number of units of enzyme required
to deglycoslyate a proteoglycan or glycoprotein will depend on many things
not least of which is the enzyme itself. BM should ship a datasheet with
your enzyme, this or a copy of BMs Biochimica Information should give
an indication of how much to use.
The state of the substrate will also be important - denaturation of the
protein core may be required for de-glycosylation.
Also be aware that complete de-glycosylation may require more than one enzyme
or the use of wide specificity enzymes. There amy be more than one type
of glycosaminoglycan chain attached to your glycoprotein.
On the subject of units BMs literature should define a unit for you,
and the enzyme suspension should be expressed in units/ml. Most biochem
textbooks should cover the definition of units of enzyme and specific
activity of an enzyme.
Hope this helps you a little
Bob Lauder R.Lauder at lancaster.ac.uk
Division of Biological Sciences Tel +(44)(0)1524 65201
Lancaster University, Lancaster, UK Fax +(44)(0)1524 843854