Background/Aims: The aim of this study was to exactly determine the pH stability of human gastric lipase (HGL) and to investigate the mechanism underlying the inactivation of HGL which occurs in gastric juice. Methods: Samples of human gastric juice and purified HGL were incubated at various pH values ranging from 0.5 to 8.0, and the residual HGL activity was measured as a function of time using the pHstat technique. Samples of purified HGL were also incubated in the presence of human pepsin. Electrophoresis and Western blot analysis were performed on all the samples in which HGL was inactivated. Results: HGL was found to be stable in gastric juice at pH values ranging from 2.0 to 7.0, especially between pH 3.0 and 5.0 (half-inactivation time >24 h). HGL activity decreased rapidly below pH 2.0 and above pH 7.0. The inactivation half times were only 43 ± 9 and 24 ± 18 min at pH 1 and pH 8, respectively. The pH stability of purified HGL was much lower than that of HGL in gastric juice. Acid or alkaline inactivation of HGL could occur without any prior proteolytic degradation, and this inactivation was irreversible. However, proteolytic degradation of HGL by pepsin also occurred at very low pH values, probably because the acid-denatured HGL is more sensitive to proteolytic cleavage by pepsin. An ex vivo study of HGL activity in several gastric juice samples showed that the HGL activity decreased with the pH of the sample, in both basal and pentagastrin-stimulated gastric juice. Conclusion: Although HGL is not as stable as it was previously thought to be under acidic conditions, it is nevertheless the most stable acid lipase and constitutes a good candidate tool for enzyme substitution therapy.

Keywords:
Gastric lipase, Pepsin, pH, Digestion
1.
Heizer WD, Cleaveland CR, Iber FL: Gastric inactivation of pancreatic supplements. Bull Johns Hopkins Hosp 1965;116:261–270.
2.
DiMagno EP, Malagelada JR, Go VL, Moertel CG: Fate of orally ingested enzymes in pancreatic insufficiency: Comparison of two dosage schedules. N Engl J Med 1977;296:1318–1322.
3.
Dutta SK, Russel RM, Iber FL: Comparative evaluation of the therapeutic efficacy of a pH-sensitive enteric coated enzyme preparation with conventional pancreatic enzyme therapy in the treatment of exocrine pancreatic insufficiency. Gastroenterology 1983;84:476–482.
4.
Regan PT, Malagelada JR, DiMagno EP, Glanzman SL, Go VLW: Comparative effects of antiacids, cimetidine and enteric coating on the therapeutic response to oral enzymes in the severe pancreatic insufficiency. N Engl Med 1977;297:854–858.
5.
Layer P, Groger G: Fate of pancreatic enzymes in the human intestinal lumen in health and pancreatic insufficiency. Digestion 1993;54:10–14.
6.
Saint-Marc Girardin MF, Cortot A, Theodore C, Laprive JP: Efficacité du pancréas total lyophilisé au cours de la pancréatite chronique et des résections pancréatiques. Gastroenterol Clin Biol 1987;11:430–431.
7.
Graham DY: Enzyme replacement therapy of exocrine pancreatic insufficiency in man: Relations between in vitro enzymes avtivities and in vivo potency in commercial pancreatic extracts. N Engl J Med 1977;296:1314–1317.
8.
Delchier JC, Vidon N, Saint-Marc Girardin MF, Soule JC, Moulin C, Huchet B, Zylberberg P: Fate of orally ingested enzymes in pancreatic insufficiency. Comparison of two dosage schedules. Aliment Pharmacol Ther 1991;5:365–378.
9.
Marotta F, O’Keffe SJD, Marks IN, Girdwood A, Young G: Pancreatic enzyme replacement therapy: Importance of gastric acid secretion, H2-antagonists and enteric coating. Dig Dis Sci 1989;34:456–461.
10.
Bommelaer G, Benque A, Moreau J, Bouisson M, Ribet A: pH-Métrie duodénale durant 24 heures dans les pancréatites chroniques. Gastroenterol Clin Biol 1984;8:403–406.
11.
Barraclough M, Taylor CJ: Twnenty-four hours ambulatory gastric and duodenal pH profiles in cystic fibrosis: Effect of duodenal hyperacidity on pancreatic enzyme function and fat absorption. J Pediatr Gastroenterol Nutr 1996;23:45–50.
12.
Laenert S, Beraud N, Castaigne JP: Pancrease gastroresistance. In vitro evaluation of pH determined dissolution. J Pediatr Gastroenterol Nutr 1987;293:994.
13.
Guarner L, Rodriguez R, Guarner F, Malagelada JR: Fate of oral enzymes in pancreatic insufficiency. Gut 1993;34:708–712.
14.
Roberts IM: Enzyme therapy for malabsorption in exocrine pancreatic insufficiency. Pancreas 1989;4:496–503.
15.
Griffin SM, Alderson D, Farndon JR: Acid resistant lipase as replacement therapy in chronic pancreatic exocrine insufficiency: A study in dogs. Gut 1989;30:1012–1015.
16.
Schneider MU, Knoll-Ruzicka ML, Domschke S, Heptner G, Domschke W: Pancreatic enzyme replacement therapy: Comparative effects of conventional and enteric-coated microspheric pancreatin and acid-stable fungal enzyme preparations on steatorrhoea in chronic pancreatitis. Hepatogastroenterology 1985;32:97–102.
17.
Moreau J, Bouisson M, Saint-Marc Girardin MF, Pignal F, Bommelaer G, Ribet A: Comparison of fungal lipase and pancreatic lipase in exocrine pancreatic insufficiency in man: Study of their in vitro properties and intraduodenal bioavailability. Gastroenterol Clin Biol 1988;12:787–792.
18.
Suzuki A, Mizumoto A, Sarr MG, Dimagno EP: Bacterial lipase and high-fat diets in canine exocrine pancreatic insufficiency: A new therapy of steatorrhea? Gastroenterology 1997;112:2048–2055.
19.
Suzuki A, Mizumoto A, Sarr MG, Rerknimitr R, Dimagno EP: Effect of bacterial or porcine lipase with low- or high-fat diets on nutrient absorption in pancreatic-insufficient dogs. Gastroenterology 1999;116:431–437.
20.
Bénicourt C, Blanchard C, Carrière F, Verger R, Junien J-L: Potential use of a recombinant dog gastric lipase as an enzymatic supplement to pancreatic extracts in cystic fibrosis; in Escobar H, Baquero CF, Suárez L (eds): Clinical Ecology of Cystic Fibrosis. Amsterdam, Elsevier, 1993, pp 291–295.
21.
Gargouri Y, Piéroni G, Rivière C, Saunière J-F, Lowe PA, Sarda L, Verger R: Kinetic assay of human gastric lipase on short- and long-chain triacylglycerol emulsions. Gastroenterology 1986;91:919–925.
22.
Carrière F, Renou C, Lopez V, De Caro J, Ferrato F, Lengsfeld H, De Caro A, Laugier R, Verger R: The specific activities of human digestive lipases measured from the in vivo and in vitro lipolysis of test meals. Gastroenterology 2000;119:949–960.
23.
Carrière F, Barrowman JA, Verger R, Laugier R: Secretion and contribution to lipolysis of gastric and pancreatic lipases during a test meal in humans. Gastroenterology 1993;105:876–888.
24.
Carrière F, Renou C, Ransac S, Lopez V, De Caro J, Ferrato F, De Caro A, Fleury A, Sanwald-Ducray P, Lengsfeld H, Beglinger C, Hadvary P, Verger R, Laugier R: Inhibition of gastrointestinal lipolysis by Orlistat during digestion of test meals in healthy volunteers. Am J Physiol Gastrointest Liver Physiol 2001;281:G16–G28.
25.
Milano S, Oliveira M: Effet d’une lipase gastrique dans un modèle d’insuffisance pancréatique exocrine chronique chez le miniporc. Gastroenterol Clin Biol 1998;22:A885.
26.
Moreau H, Gargouri Y, Lecat D, Junien J-L, Verger R: Screening of preduodenal lipases in several mammals. Biochim Biophys Acta 1988;959:247–252.
27.
Fink CS, Hamosh P, Hamosh M: Fat digestion in the stomach: Stability of lingual lipase in the gastric environment. Pediatr Res 1984;18:248–254.
28.
Aoubala M, Douchet I, Laugier R, Hirn M, Verger R, De Caro A: Purification of human gastric lipase by immunoaffinity and quantification of this enzyme in the duodenal contents using a new ELISA procedure. Biochim Biophys Acta 1993;1169:183–188.
29.
Lowry OH, Rosebrough NJ, Farr AL, Randall RJ: Protein measurement with the Folin phenol reagent. J Biol Chem 1951;193:265–275.
30.
Will PC, Allbe WE, Witt CG, Bertko RJ, Gaginella TS: Quantification of pepsin A activity in canin and rat gastric juice with the chromogenic substrate Azocoll. Clin Chem 1986;30:107–111.
31.
Laemmli UK: Cleavage of structural proteins during the assembly of the head of bacteriophage T4. Nature 1970;227:680–685.
32.
Gershoni JM, Palade GE: Electrophoretic transfer of proteins from sodium dodecyl sulfate-polyacrylamide gels to a positively charged membrane filter. Anal Biochem 1982;124:396–405.
33.
Moreau H, Gargouri Y, Laugier R, Verger R. Gastric lipases: Biochemical and physiological studies; in Shukla VKS, Hølmer G (eds): 15th Scandinavian Symposium on Lipids. Skøping, Rebild Bakker, 1989, pp 268–292.
34.
Carrière F, Raphel V, Moreau H, Bernadac A, Devaux M-A, Grimaud R, Barrowman JA, Bénicourt C, Junien J-L, Laugier R, Verger R: Dog gastric lipase: Stimulation of its secretion in vivo and cytolocalization in mucous pit cells. Gastroenterology 1992;102:1535–1545.
35.
Carrière F, Laugier R, Barrowman JA, Douchet I, Priymenko N, Verger R: Gastric and pancreatic lipase levels during a test meal in dogs. Scand J Gastroenterol 1993;28:443–454.
36.
DeNigris SJ, Hamosh M, Kasbekar DK, Lee TC, Hamosh P: Lingual and gastric lipases: Species differences in the origin of prepancreatic digestive lipases and in the localization of gastric lipase. Biochim Biophys Acta 1988;959:38–45.
37.
Moreau H, Laugier R, Gargouri Y, Ferrato F, Verger R: Human preduodenal lipase is entirely of gastric fundic origin. Gastroenterology 1988;95:1221–1228.
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2002
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