title: Antigenic relatedness between human lecithin-cholesterol acyltransferase and phospholipases of the A2 family.
abstract: A monoclonal antibody, B10, generated against pure human lecithin-cholesterol acyltransferase (EC 2.3.1.43) caused the inhibition of the esterolytic and cholesterol esterifying activities of the enzyme. This antibody also reacted with a number of pancreatic and snake venom phospholipases A2 species but not phospholipase A1. A concentration-dependent inhibition of phospholipase A2 was also seen in the presence of B10. Treatment of lecithin-cholesterol acyltransferase or B10-reacting phospholipases with phenacyl bromide, a reagent known to interact with the active site of phospholipase A2, inhibited both their esterolytic activity and their capacity to bind to B10. A dimeric phospholipase A2 species with a known occluded active site did not cross-react with B10. Thus, lecithin-cholesterol acyltransferase and some enzymes of the phospholipase A2 family share a common antigenic determinant which is probably located near or at their esterolytic active site.
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D003429:Cross Reactions; D006801:Humans; D007862:Phosphatidylcholine-Sterol O-Acyltransferase / Q000276:immunology*; D010713:Phosphatidylcholines; D010740:Phospholipases / Q000276:immunology*; D010741:Phospholipases A / Q000276:immunology*; D054466:Phospholipases A1; D054467:Phospholipases A2; D002785:Sterol O-Acyltransferase / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D010713:Phosphatidylcholines; D002785:Sterol O-Acyltransferase; D007862:Phosphatidylcholine-Sterol O-Acyltransferase; D010740:Phospholipases; D010741:Phospholipases A; D054466:Phospholipases A1; D054467:Phospholipases A2