1. The presence of lipoprotein lipase has been confirmed in acetone-ether extracts of human adipose tissue.
2. The properties of the enzyme appear to be similar to that in rat adipose tissue though it is less active on a weight basis.
3. The presence of a separate monoglyceride lipase has been demonstrated in human adipose tissue.
4. In eluates of human adipose tissue the activity of lipoprotein lipase is dependent on heparin, whereas that of the monoglyceride lipase does not require heparin.
5. No consistent effect of insulin in vitro on the enzyme in human adipose tissue has been demonstrated. Possible reasons for this are discussed.