Purification and characterization of a novel lipase from the digestive glands of a primitive animal: the scorpion.
Higher animal's lipases are well characterized, however, much less is known about lipases from primitive ones. We choose the scorpion, one of the most ancient invertebrates, as a model of a primitive animal. A lipolytic activity was located in the scorpion digestive glands, from which a scorpion digestive lipase (SDL) was purified. Pure SDL, a glycosylated protein, has a molecular mass of 50 kDa, it presents the interfacial activation phenomenon. It was found to be more active on short-chain triacylglycerols than on long-chain triacylglycerols. SDL is a serine enzyme and possesses one accessible sulfhydryl group which is not essential for the catalysis. Among the NH2-terminal 33 residues, a 17 amino acids sequence shows similarities with sequence of Drosophila melanogaster putative lipase. Interestingly, neither colipase, nor bile salts were detected in the scorpion hepatopancreas. This indicates that colipase evolved in vertebrates simultaneously with the appearance of an exocrine pancreas and a true liver which produces bile salts. Furthermore, polyclonal antibodies directed against SDL failed to recognise the classical digestive lipases. Altogether, these results suggest that SDL is a member of a new group of digestive lipases belonging to invertebrates.
Zouari
Nacim
N
Laboratoire de Biochimie et de Génie Enzymatique des Lipases, ENIS, BPW route de Soukra, 3038 Sfax, Tunisia.
Miled
Nabil
N
Cherif
Slim
S
Mejdoub
Hafedh
H
Gargouri
Youssef
Y
D000595:Amino Acid Sequence; D000818:Animals; D015153:Blotting, Western; D004064:Digestive System / Q000201:enzymology*; D004591:Electrophoresis, Polyacrylamide Gel; D004797:Enzyme-Linked Immunosorbent Assay; D043143:Hepatopancreas / Q000378:metabolism; D008049:Lipase / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D008969:Molecular Sequence Data; D012605:Scorpions / Q000201:enzymology*; D016415:Sequence Alignment; D020539:Sequence Analysis, Protein; D014280:Triglycerides / Q000378:metabolism
D014280:Triglycerides; D008049:Lipase; C031627:tripropionin