Data Discussion:

1. Is there a difference between the pattern of acid phosphatase and uricase?
2. Is there a difference between the pattern of acid phosphatase and cathepsin?
3. Is there a difference between the pattern of acid phosphatase and cytochrome oxidase?
4. Is there a difference between the pattern of acid phosphatase and glucose-6-phosphatase?
5. Why is sucrose used in the homogenization medium? How about water?
6. What would be the expected result if a different centrifugation speed has been selected?
7. Why the fractionation steps only enrich for organelles and cannot yield a pure fraction of organelles?

Expected results:
The enzyme distribution pattern shows a novel fraction containing acid hydrolases (some enzyme assays have been performed at acidic pH, pH 5).  This experiment is similar to the one originally described in 1955 for the discovery of the lysosome.  By density gradient centrifugation, the organelle containing uricase can be separated from the lysosome as a separate organelle (peroxisome).  Dr. Christian de Duve, who made this discovery together with his colleagues, was awarded a Nobel prize in 1974 for his discovery of lysosomes and peroxisomes.  Lysosomes serve a wide range of cellular degradative processes and the lack of lysosomal enzymes, such as acid phosphatase, leads to lysosomal storage diseases.

References:
C. DeDuve et al. 1955 Tissue fractionation studies 6. Intracellular distribution patterns of enzymes in rat liver tissue. Biochem J 60, 604.
H.G. Hers & F. van Hoof 1973 Lysosomes and Storage Diseases, Academic Press, New York.
J. Lindsten 1992 Nobel Lectures Physiology or Medicine 1971-1980, World Scientific, Singapore.
J.B. Lloyd & R.W. Mason 1996 Biology of the Lysosome. Plenum, New York.
D.L. Spector et al. 1998 Cells; A Laboratory Manual, Cold Spring Harbor Press, Cold Spring Harbor, New York.
L.A. Seidman & C.J. Moore 2000 Basic Laboratory Methods for Biotechnology, Prentice Hall, New Jersey.