Proteolytic cleavage of ostrich and turkey pancreatic lipases: production of an active N-terminal domain.
OBJECTIVE
The aim of this study was to check some biochemical and structural properties of ostrich and turkey pancreatic lipases (OPL and TPL, respectively).


METHODS
Limited proteolysis of OPL and TPL was performed in conditions similar to those reported for porcine pancreatic lipase.


RESULTS
In the absence of bile salts and colipase, OPL failed to catalyze the hydrolysis of pure tributyrin or efficiently hydrolyze olive oil emulsion. When bile salts and colipase were preincubated with the substrate, the OPL kinetic behavior remained linear for more than 30 minutes. The enzyme presented a penetration power value into an egg phosphatidylcholine monomolecular film that was comparable to that of HPL and lower than that of TPL. Chymotrypsin, trypsin, and thermolysin were able to hydrolyze OPL and TPL in different ways. In both cases, only N-terminal fragments accumulated during the hydrolysis, whereas no C-terminal fragment was obtained in either case. Tryptic cleavage of OPL and TPL completely degraded the enzymes. Nevertheless, chymotryptic attack generated 35-kd and 43-kd forms for TPL and OPL, respectively. Interestingly, the OPL 43-kd form was inactive, whereas the TPL 35-kd protein conserved its lipolytic activity.


CONCLUSIONS
OPL, TPL, and mammal pancreatic lipases share a high amino acid sequence homology. Further investigations are, however, needed to identify key residues involved in substrate recognition responsible for biochemical differences between the 2 classes of lipases.
Ben Bacha
Abir
A
Laboratoire de Biochimie et de Génie Enzymatique des Lipases, Ecole Nationale d'Ingénieurs de Sfax, Tunisia.
Fendri
Ahmed
A
Gargouri
Youssef
Y
Mejdoub
Hafedh
H
Miled
Nabil
N
D000595:Amino Acid Sequence; D000818:Animals; D002918:Chymotrypsin / Q000378:metabolism; D003089:Colipases / Q000494:pharmacology; D003840:Deoxycholic Acid / Q000494:pharmacology; D019787:Linoleic Acid / Q000378:metabolism; D008049:Lipase / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D008969:Molecular Sequence Data; D000069463:Olive Oil; D010179:Pancreas / Q000201:enzymology*; D010713:Phosphatidylcholines / Q000378:metabolism; D010938:Plant Oils / Q000378:metabolism; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity; D020310:Struthioniformes / Q000378:metabolism*; D013379:Substrate Specificity; D013657:Taurodeoxycholic Acid / Q000494:pharmacology; D013820:Thermolysin / Q000378:metabolism; D014280:Triglycerides / Q000378:metabolism; D014357:Trypsin / Q000378:metabolism; D014422:Turkeys / Q000378:metabolism*
D003089:Colipases; D000069463:Olive Oil; D010713:Phosphatidylcholines; D010938:Plant Oils; D014280:Triglycerides; D003840:Deoxycholic Acid; D013657:Taurodeoxycholic Acid; D019787:Linoleic Acid; D008049:Lipase; D002918:Chymotrypsin; D014357:Trypsin; D013820:Thermolysin; C005830:tributyrin