Characterization of all the lipolytic activities in pancreatin and comparison with porcine and human pancreatic juices

Abstract

Porcine pancreatic extracts (PPE), also named pancreatin, are commonly used as a global source of pancreatic enzymes for enzyme replacement therapy in patients with exocrine pancreatic insufficiency. They are considered as a good substitute of human pancreatic enzymes and they have become a material of choice for in vitro models of digestion. Nevertheless, while the global PPE contents in lipase, protease and amylase activities are well characterized, little is known about individual enzymes. Here we characterized the lipase, phospholipase, cholesterol esterase and galactolipase activities of PPE and compared them with those of porcine (PPJ) and human (HPJ) pancreatic juices. The phospholipase to lipase activity ratio was similar in PPJ and HPJ, but was 4-fold lower in PPE. The galactolipase and cholesterol esterase activities were found at lower levels in PPJ compared to HPJ, and they were further reduced in PPE. The enzymes known to display these activities in HPJ, pancreatic lipase-related protein 2 (PLRP2) and carboxylester hydrolase/bile salt-stimulated lipase (CEH/BSSL), were identified in PPJ using gel filtration experiments, SDS-PAGE and LC-MS/MS analysis. The galactolipase and cholesterol esterase activities of PPE indicated that PLRP2 and CEH/BSSL are still present at low levels in this enzyme preparation, but they were not detected by mass spectrometry. Besides differences between porcine and human enzymes, the lower levels of phospholipase, galactolipase and cholesterol esterase activities in PPE are probably due to some proteolysis occurring during the production process. In conclusion, PPE do not provide a full substitution of the lipolytic enzymes present in HPJ.

The digestion of galactolipids and its ubiquitous function in Nature for the uptake of the essential α-linolenic acid

“…No significant hydrolysis of galactolipids was observed during the gastric phase, thus confirming that gastric lipase has no galactolipase activity.MGDG and DGDG from both spinach and pea vine haulm CRFs were however largely converted into MGMG, DGMG (Figures 9A and B) and FFA (Figure 11Cand D) during the intestinal phase, with conversion rates >80% for MGDG and >60% for DGDG after 60 minutes of incubation with pancreatic enzymes. It was observed that the digestion of CRF galactolipids by PPE is less effective than the digestion by HPJ, in good agreement with the fact that PPE contains lower levels of galactolipase activity compared to HPJ107 . The composition of FFA was similar to the FA composition of the whole CRF, with a large proportion of ALA (55.38 ± 1.33% w/w of the total FA in spinach leave CRF and 37.82 ± 0.31% w/w of the total FA in pea vine haulm CRF).…”

“…Further characterizations of PLRP2 in rat 86,104 , horse 105 , rabbit 105 , and humans 67,87,101,106 have confirmed the galactolipase activity of PLRP2, as well as the fact that it is the most active galactolipase present in the exocrine pancreatic secretion 67,79,104 ( Table 4). Recently, PLRP2 was also identified in porcine pancreatic juice 107 . This later study confirmed that galactolipase activity in both human and porcine pancreatic juices is associated with two protein fractions of around 100 and 50 kDa, containing CEH and PLRP2, respectively.…”

“…This later study confirmed that galactolipase activity in both human and porcine pancreatic juices is associated with two protein fractions of around 100 and 50 kDa, containing CEH and PLRP2, respectively. Although human CEH has a lower specific activity than HPLRP2 (Table 4), it is present at higher levels than HPLRP2 in human pancreatic juice and duodenal contents 107,108 and one can assume that it has also a significant contribution to galactolipid digestion. In some species, like Zebrafish, PLRP2 is not present while genes encoding homologs to pancreatic CEH can be found using a BLAST search (see Genebank AAH55668 and NCBI Reference Sequence NP_001020344.2).…”

“…With 531 amino acid residues in the predicted mature proteins, these two zebrafish CEH are shorter than human pancreatic CEH (733 amino acid residues; UniProtKB/Swiss-Prot: P19835.3). This is due to the absence of a large C-terminal region made of proline-rich tandem repeats of 11 amino acids ( Figure 10), with 17 repeats in human CEH (some variations between individuals can be observed) and various numbers of repeats in other mammalian species (4 in porcine CEH 107 ). The absence of the C-terminal region was previously reported for the CEH-BSSL of another fish species, the salmon 146 .…”

Polar Lipids Reduce In Vitro Duodenal Lipolysis Rate of Oat Oil and Liquid Oat Base Products

“…This lipolysis rate is approximately tenfold lower compared to values obtained when using tributyrin as a substrate. [ 33 ] This might be due to differences in pancreatic lipase activity toward TAG with long‐chain FA. [ 34 ] Substantially lower lipolysis rates were obtained for emulsions of oat oils ( p ≤ 0.001) and the rate decreased with increasing concentration of polar lipids in the oat oil.…”