Purification of two lipases with high phospholipase A1 activity from guinea-pig pancreas.
1. Two cationic lipases (Ia and Ib) were purified from homogenates of fresh guinea-pig pancreas by ion-exchange chromatography on DEAE-Sepharose and CM-Sepharose (twice for the latter) followed by gel filtration on Sephadex G-100. 2. Both enzymes were homogeneous upon polyacrylamide gel electrophoresis. Their molecular weights are 37,000 and 42,000 for lipases Ia and Ib, respectively, as determined by gel filtration on Sephadex G-100. Very close values for isoelectric points were found in the pH range 9.3-9.4. 3. The cationic lipases are characterized by a high phospholipase A activity (500 IU/mg protein using a potentiometric assay with egg yolk lecithin as substrate), resulting in an unusual phospholipase/lipase activity ratio of 1. 4. Using doubly labelled phosphatidylcholine, a specificity, A1, was described for the two enzymes, which are unaffected by N-ethylmaleimide, diisopropylfluorophosphate and p-bromophenacylbromide. The enzymes are insensitive to EDTA and slightly inhibited by CaCl2 and MgCl2, whereas sodium deoxycholate is required for maximal activity.
D000818:Animals; D002417:Cattle; D004355:Drug Stability; D006168:Guinea Pigs; D006736:Horses; D007526:Isoelectric Point; D008049:Lipase / Q000302:isolation & purification / Q000378:metabolism*; D008970:Molecular Weight; D010179:Pancreas / Q000201:enzymology*; D010713:Phosphatidylcholines / Q000378:metabolism; D010740:Phospholipases / Q000378:metabolism*; D010741:Phospholipases A / Q000378:metabolism*; D054466:Phospholipases A1
D010713:Phosphatidylcholines; D010740:Phospholipases; D008049:Lipase; D010741:Phospholipases A; D054466:Phospholipases A1