Acid Lipase in the Liver of Domestic Fowl: Subcellular Localization and Some Properties

Abstract

Most of the lipase in the liver of domestic fowl was acid lipase, found in the 11, 700 × g pellet of the liver. About two-thirds of the enzyme in the pellet was solubilized in hypotonic solution. The solubilized lipase was stable in 40% ethylene glycol at -70°C for 40 days, but was labile during chromatographies even with 20% ethylene glycol at 4°C. The molecular weight of the lipase was about 34, 000 by Sephacryl S-300gel filtration, and the pi was about 5.4 by isoelectric focusing. The enzyme had its maximum activity at pH 6.0, and 40°C, and was stable below 40°C. Bovine and chicken serum albumins activated the enzyme. Ca²⁺, Mg²⁺, Mn²⁺, and Zn²⁺ increased the lipase activity, but EDTA decreased the activity. CHAPS and octyl glucoside increased the lipase activity at low concentrations, but other detergents greatly inhibited the lipase activity. Serum of laying hens greatly decreased the lipase activity.