BIOCHEMICAL-PROPERTIES OF CLONED LIPASES FROM THE PSEUDOMONAS FAMILY

Three Pseudomonas lipases, representing three subfamilies, were analys ed for pH optima, destabilization by EGTA and surfactants, phospholipa se and cholesterolesterase side activities. All the Pseudomonas lipase s tested showed alkaline pH optima. The Pseudomonas cepacia and the P. pseudoalcaligenes lipases were totally inhibited by EGTA at pH 9, and the latter was also fully inhibited at pH 7. The lipase from P. mendo cina was not inhibited by EGTA at: any of the pH values tested. These findings indicate that a calcium binding site exists in some of the Ps eudomonas lipases. The P. pseudoalcaligenes, P. cepacia and P. mendoci na lipases were inhibited by the anionic surfactant SDS at concentrati ons between 0.01-0.5 mg/ml. The P. pseudoalcaligenes and P. cepacia li pases were not inhibited by the nonionic surfactant Brij35 in concentr ation up to 1 mg/ml, whereas the lipase from P. mendocina was inhibite d at 0.1 mg/ml. The P. pseudoalcaligenes and P. cepacia lipases were f ound to possess high cholesterol esterase activity. P. pseudoalcaligen es lipase was further found to have high phospholipase activity. Ten P seudomonas lipase sequences were compared by automatic sequence alignm ent. On the basis of sequence identity we have classified Pseudomonas lipases into five subfamilies.