ACID LIPASE INHIBITOR IN CHICKEN PLASMA IDENTIFIED AS APOLIPOPROTEIN-A-I

We have reported a inhibitor of acid lipases in liver lysosomes and er ythrocytes from chickens [M, Fujii et al., Int. J. Biochem., 22, 895-8 98 (1990)]. In this paper, the properties of the inhibitor were descri bed in comparison with those of apo A-I of chicken. The purified inhib itor migrated with the same mobility on SDS-PAGE as apo A-I, and had a molecular weight of 27,000. The peptide map from the lipase inhibitor was similar to that of apo A-I. Antibodies to the acid lipase inhibit or also reacted with apo A-I, Apo A-I inhibited the acid lipase activi ties of liver lysosomes and erythrocytes from chickens as strongly as the lipase inhibitor, The N-terminal amino acid sequence of lipase inh ibitor was identical to that of apo A-I as far as residue 20. The amin o acid sequence of peptides obtained from the inhibitor by cleavage wi th CNBr corresponded to internal sequence of apo A-I, and so the CNBr- peptides were derived by cleavage after the methionine residues in apo A-I. The findings showed that the inhibitor of the acid lipases in li ver lysosomes and erythrocytes from chickens was identical to apo A-I.