Dromedary pancreatic lipase: Purification and structural properties

Abstract

Dromedary pancreatic lipase was purified from delipidated pancreases. Pure dromedary pancreatic lipase (glycerol ester hydrolase, EC 3.1.1.3) was obtained after ammonium sulfate fractionation, Sephadex G-100 gel filtration, anion-exchange (Mono Q Sepharose) and size exclusion column using high performance liquid chromatography (HPLC). The pure lipase is a monomer and has a molecular mass of about 45 kD and a p I of around 4.8. A specific activity of 5900 U/mg was measured on tributyrin as substrate at 37°C in the presence of colipase and 2 mM NaTDC. The first 11 N-terminal amino acid residues and 10 peptides obtained by endoproteinase Glu-C digestion were sequenced. Dromedary pancreatic lipase is very similar to other pancreatic lipases as compared with their N-terminal and some peptides sequences. DrPL is activated by interfaces. The interfacial activation could be related to the presence of a lid and in fact one fragment of this lid domain (P9) was sequenced here: its' role will be discussed below.