Purification, properties, and substrate specificity of a carboxylesterase in pancreatic juice.

An esterase activity was purified from rat pancreatic juice by DEAE cellulose chromatography, hydroxylapatite chromatography, and filtration through Sephadex G-100. After this procedure the enzyme was purified 200 times with a yield of 12%. The enzyme had a molecular weight of around 70,000 and an isoelectric point of 5.0. It had a wide substrate specificity and hydrolysed water-soluble esters as well as water-insoluble esters when dispersed with bile salt. Bile salt strongly stimulated the esterase activity, caused aggregation of the enzyme monomer into a polymer form, and protected the activity against proteolytic inactivation. On the basis of the low substrate specificity, the enzyme should be classified as a carboxylic esterase. It most probably is identical with sterolester hydrolase.