enzyme activity measurement - (Jan/15/2006 )

I am a new researcher in the field of enzymology. I want your help in this subject.
I want to measure the activity of enzyme extracted from the cancer cells. I came to know about one protocol that in which they resuspened the cells in the TE buffer+ aprotinin after trypsinization and then put the microfuge tube into the N2 tank for few secs and stored in the deep freezer. The next day they measure the enzyme activity. I am confused in which step the cells are lyzed so as to liberate the enzymes from the cells.They dont use any of the lysis solution and detergents.
Please help me to clarify my confusion.
Thank you very much in advance.

Just the fast freeze, thawing step andso the temperature change lysed the cells