Separation and Further Characterization of Human Adipose Tissue Neutral and Alkaline Lipolytic Activities

Neutral lipolytic activity (hydrolysis of olive oil at 37°, pH 7.0) and alkaline lipolytic activity (hydrolysis of tributyrin at 47°, pH 8.0) have previously been demonstrated in human adipose tissue. Neutral lipolytic activity has currently been shown to be present in a large molecular weight substance, associated with lipid, and separable from most alkaline lipolytic activity by ammonium sulfate precipitation and Sephadex G-200 gel filtration. Alkaline lipolytic activity (ALA) has been shown to exist as three separable fractions: ALA-I, ALA-II, and ALA-III. ALA-I represents a small percentage of the total alkaline lipolytic activity, is eluted from Sephadex with neutral lipolytic activity, exists as a lipid-protein complex of ALA-II, and has no mobility during starch gel electrophoresis. ALA-II is a smaller molecule than ALA-I and exists primarily as four electrophoretically separable bands of activity. ALA-III is considerably smaller than ALA-II, is a subunit of ALA-II, and exists primarily as a fifth band of electrophoretically separable activity.