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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Extraction, purification, and characterization of the lipase from the viscera of porgy (Stenotomus chrysops)

Tian, Feng, 1980- January 2008 (has links)
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).
2

Extraction, purification, and characterization of the lipase from the viscera of porgy (Stenotomus chrysops)

Tian, Feng, 1980- January 2008 (has links)
No description available.

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