Molecular cloning of the cDNA for rat hepatic, bile salt-dependent cholesteryl ester/retinyl ester hydrolase demonstrates identity with pancreatic carboxylester lipase.

Rat liver homogenates contain a neutral lipid ester hydrolase that requires millimolar concentrations of bile salts for maximal activity in catalyzing the hydrolysis of cholesteryl esters and retinyl esters in vitro. Previous studies have demonstrated that this hepatic hydrolase resembles rat pancreatic carboxylester lipase because it reacts with a specific pancreatic carboxylester lipase antibody and the eight N-terminal amino acids of the hepatic protein are identical to those of the pancreatic enzyme. Nonetheless, the exact molecular relationship between the hepatic and pancreatic enzymes is unclear. In the present study, a rat hepatic cDNA encoding the enzyme was cloned. Sequence analysis demonstrated that this cDNA corresponds to the full-length mature pancreatic carboxylester lipase (EC# 3.1.1.13). In individual animals the hepatic and pancreatic cDNA sequences were identical. However, among rats there were sequence variations, suggesting a polymorphic nature for this rat gene.