Hydrolysis characteristics of bovine milk fat and monoacid triglycerides mediated by pregastric lipase from goats and kids.
Commercial extracts from oro-pharyngeal tissues of goats and kids have been used as the source of pregastric lipase and have been processed to yield partially purified samples of the primary pregastric lipase. The activity of these lipases against tributyrylglycerol has been determined over a range of pH and temperatures. Optimum pH conditions for pregastric lipase ranged from pH 5.6 to 6.5 for goats and from pH 5.5 to 6.2 for kids, respectively; the optimum temperature ranged from 43 to 60 degrees C. Optima for kid lipase extended slightly below pH 5.5 and higher than 60 degrees C; which were the limits of the test conditions. The enzymes were also used as catalysts for the hydrolysis of monoacid triglycerides (C4:0 to C12:0) at 40 degrees C and pH 6.5; activity was maximum against tributyrylglycerol (C4:0). Values for the Michaelis-Menten constant, increased as carbon chain length of the carboxylic moiety on the triglycerides increased, but values were identical for pregastric lipases of both goats and kids. Anhydrous milk fat was hydrolyzed by the commercial extracts of pregastric lipases of goats and kids, and the resulting profiles for free fatty acids were very similar to one another and to the corresponding profile for a commercial sample of Parmesan cheese. There appear to be no significant differences in activity between the enzyme preparations from goats and kids.
Lai
D T
DT
Department of Chemistry, University of Auckland, New Zealand.
MacKenzie
A D
AD
O'Connor
C J
CJ
Turner
K W
KW
D000818:Animals; D002417:Cattle; D004655:Emulsions; D006041:Goats / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007700:Kinetics; D008049:Lipase / Q000378:metabolism*; D050356:Lipid Metabolism; D008892:Milk / Q000737:chemistry*; D013696:Temperature; D014280:Triglycerides / Q000378:metabolism*
D004655:Emulsions; D014280:Triglycerides; D008049:Lipase; C005830:tributyrin