Studies on the properties of phospholipase A1 in liver lysosomes of chloroquine-treated rats.

The influence of chloroquine on phospholipase A1 (acid pH optimum) activity was studied in subcellular fractions of rat liver after intraperitoneal application of the drug for 9, 12 and 21 days. In comparison with other cell fractions lysosomes of treated rats contained the highest enzyme activity with a pH optimum of 4.0. The activity of phospholipase A1 in lysosomes showed a direct relationship to the number of days of chloroquine treatment. The effects of the incubation time, Ca2+, Hg2+, enzyme and substrate concentration on phospholipase A1 activity were studied.