Summary
A novel method is described for measuring the incorporation of radiolabelled amino
acids into rat adipose tissue lipoprotein lipase (LPL) in vitro. Following the incubation of epididymal fat-bodies in the presence of [3H]leucine, the radiolabelled enzyme was isolated from extracts of the delipidated
tissue, in a single step, by affinity chromatography on heparin-Sepharose, SDS-PAGE
of such purified enzyme preparations revealed the presence of a single radiolabelled
polypeptide of molecular weight 56000, corresponding to LPL. In the presence of insulin,
the rates of incorporation into LPL and into total tissue protein were increased respectively
by 2.3 fold and 1.7 fold, compared to controls. It is concluded that part of the increase
in incorporation into LPL is due to the general stimulus of protein synthesis in the
tissue by insulin. Additionally insulin may either specifically increase the rate
of synthesis or decrease the rate of degradation of the enzyme.
Key-Words:
Lipoprotein Lipase
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Insulin
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Adipose Tissue
