Bile salt stimulated lipase: Inhibition by phospholipids and relief by phospholipase A 2 .

Introduction: Bile salt stimulated lipase (BSSL; Enzyme Commission (EC) number 3.1.1.13) has been a candidate triglyceridase for improving enzyme therapy for pancreatic insufficiency; however, its efficacy is near absent. We hypothesise that similarly to pancreatic lipase, BSSL is inhibited by phospholipids and this inhibition is relieved by Phospholipase A ₂ (PLA ₂ ; EC 3.1.1.4), and the present study was undertaken to explore this possibility.
Materials and Methods: Synthetic emulsions of triglyceride and phosphatidylcholine (PC) or lysophosphatidylcholine (LPC)/bile salt mixed micelles were used as a model of intestinal digestion-media. The effect of PLA ₂ treatment of systems containing PC on BSSL activity was also explored. Automatic titration at constant pH (pH-stat) and nuclear magnetic resonance (NMR) spectroscopy were used to measure the rate and identify products of lipolysis.
Results: PC was inhibitory to BSSL activity, while LPC became inhibitory only above an LPC/bile salt concentration ratio of 0.3. PLA ₂ treatment relieved the inhibition only below this ratio, despite its complete phospholipid-hydrolysing action. Thus, LPC had an inhibitory effect at higher concentrations.
Conclusions: These results may implicate a change in the design of enzyme therapy in patients with pancreatic exocrine insufficiency. Supplementation of BSSL with PLA ₂ could improve patient health with adequate manipulation of phospholipid and lysophospholipid concentrations in the intestinal fluid.
(Copyright © 2017 European Cystic Fibrosis Society. Published by Elsevier B.V. All rights reserved.)