We propose to examine the effects of diet and hypolipidemic drugs on the activity of aortic cholesterol esterase (EC 3.1.1.13). We find both synthetic and hydrolytic activity in an acetone powder prepared from aorta. Thus for each treatment we will assay synthetic (S) and hydrolytic (H) activity and compare S/H ratios for various treatments. We have also found that a protein (which is precipitable at pH 5.7) present in the acetone powder inhibits cholesteryl ester synthetase activity. We will work on identification of this material and will also seek to ascertain how diet and drugs affect its concentration. In the course of other studies we noticed that sera of cancer patients show significantly elevated levels of the B isozyme (heat stable) of hexosaminidase. We are engaged in a double blind study in an effort to confirm this finding.