extracellular chymotrypsin digestion

[Cynthia Bolognese]

I am looking for details on the technique of digesting plasma membrane 
bound proteins with chymotrypsin. The goal is to treat yeast cells with 
extracellular chymotrypsin in order to determine the orientation of our 
membrane bound protein. I would like to know if anyone can recommend a 
refernce that would give me a starting concentration of chymotrypsin, 
digestion buffer, and the pros and cons of whole yeast cells vs. 
spheroplasts. Please email me with suggestions.

Thanks in advance,
Cynthia Bolognese
bolognes at umbc7.umbc.edu