Lipolysis in Turkey Muscle: Association of Lipid Hydrolase Activities with Zinc and Copper Metalloproteins in a High‐Molecular Weight Lipid‐Protein Aggregate

Lipids of stored turkey meat undergo lipolytic and oxidative degradation; partial characterization of the lipolytic activity was achieved. Gel filtration of turkey thigh muscle cytosol revealed a lipid‐protein aggregate with the major lipolytic activity. This aggregate exhibited a molecular weight of approximately 2 ± 10⁶ daltons, and contained approximately 45% lipids, and was associated with zinc and copper. Incubation of this aggregate, or cholate treatment, resulted in the appearance of lower molecular weight lipolytically active fractions. Two of these fractions, one containing copper and zinc, the second, zinc, were partially purified by ion‐exchange chromatography and gel filtration, and had molecular weights and amino acid compositions similar to those reported for rat liver copper‐chelatins. The inhibition characteristics of the lipolytic activity was similar to other lipases.