高等植物における脂質分解酵素の存在とその馬鈴薯塊茎中における細胞内分布

Lipolytic acyl-hydrolase existed in potato tubers, the leaves of potato, bean, and soybean as well as rice grains with a relatively high activity, but spinach leaves, cabbage, sweet potato, and carrot root showd little or no activity under the present enzyme assay conditions.
During the incubation of the homogenate of potato tubers, the membrane lipids were rapidly hydrolyzed by endogenous lipolytic enzymes. When diisopropyl fluorophosphate (1 mM) was added to the homogenate, the degradation of the membrane lipids was retarded. The subcellular fractionation in the presence and absence of the inhibitor showed that the enzyme was mostly present in the supernatant fraction (about 90% of total activity). But, with other evidence it is possible that the enzyme occurs in some fragile organelles such as vacuoles and was mixed with the soluble fraction by the disruption of the organelles.
The molecular weight of the enzyme in the supernatant and mitochondria fractions was estimated to be 132,000, which differed from that of the purified enzyme (70,000) described previously.