Lipase, from porgy (Stenotomus chrysops) viscera, was purified by polyethylene glycol (PEG) 1000 precipitation, followed by dialysis and affinity chromatography on EAH-Sepharose 48. The digestive lipase from porgy showed seasonal variation in activity with high activity found in late summer and early fall compared with a spring sample. Polyethylene glycol (PEG) precipitation fraction was used to characterize this enzyme using p-nitrophenyl palmitate (pNPP) as substrate. Porgy lipase did not behave like a bile salt activated/depended lipase because it was able to hydrolyze pNPP without bile salt (e.g., sodium cholate). Porgy lipase was stable within the pH range of pH 6.0-10.0, with an optimum activity at pH 8.5. The enzyme was quite stable at temperatures below 40°C, but lost its activity rapidly at temperatures above 40°C. The optimum activity for hydrolysis pNPP was at 40°C, but the enzyme also demonstrated relatively high activity at temperatures below 40°C (i.e., 10-40°C) as well. Detergents, Triton X-100, Tween 40 and Tween 80, at final concentrations of 0.5 mM and 1 mM were found to have inhibitory effects on porgy digestive lipase activity. However, all three tested detergents appeared to increase the activity of porgy digestive lipase at elevated temperatures (i.e., 60-80°C).
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.111549 |
| Date | January 2008 |
| Creators | Tian, Feng, 1980- |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Master of Science (Department of Food Science and Agricultural Chemistry.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 003132363, proquestno: AAIMR66729, Theses scanned by UMI/ProQuest. |
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