Kinetic properties of human milk bile salt-activated lipase: studies using long chain triacylglycerol as substrate. 1985

C S Wang, and D M Lee

Studies on the hydrodynamic properties of human milk bile salt-activated lipase (BAL) indicated that it is a monomer with molecular weight of 107,000. The presence of taurocholate (1 mM) did not lead to an association of the enzyme. The enzyme had a basal activity with trioctanoylglycerol and with shorter chain, but not with longer chain, monoacid triacylglycerols. Based on kinetic analyses, we suggest that the BAL-catalyzed lipolysis of long-chain triacylglycerol can be described to follow a compulsory sequential mechanism. The initial interaction of BAL with the activator (taurocholate) leads to a conformational change of the enzyme which facilitates the further interaction with the long chain triacylglycerol substrate in forming the enzyme-bile salt-substrate ternary complex. We also suggest that the binding of BAL with substrate involves direct interaction of the active site with the fatty acyl-chain of the triacylglycerol rather than with nonspecific hydrophobic interactions at the emulsion interface.

UI MeSH Term Description Entries
D007700 Kinetics The rate dynamics in chemical or physical systems.
D008049 Lipase An enzyme of the hydrolase class that catalyzes the reaction of triacylglycerol and water to yield diacylglycerol and a fatty acid anion. It is produced by glands on the tongue and by the pancreas and initiates the digestion of dietary fats. (From Dorland, 27th ed) EC 3.1.1.3. Triacylglycerol Lipase,Tributyrinase,Triglyceride Lipase,Acid Lipase,Acid Lipase A,Acid Lipase B,Acid Lipase I,Acid Lipase II,Exolipase,Monoester Lipase,Triacylglycerol Hydrolase,Triglyceridase,Triolean Hydrolase,Hydrolase, Triacylglycerol,Hydrolase, Triolean,Lipase A, Acid,Lipase B, Acid,Lipase I, Acid,Lipase II, Acid,Lipase, Acid,Lipase, Monoester,Lipase, Triglyceride
D008895 Milk, Human Milk that is produced by HUMAN MAMMARY GLANDS. Breast Milk,Human Milk,Milk, Breast
D008970 Molecular Weight The sum of the weight of all the atoms in a molecule. Molecular Weights,Weight, Molecular,Weights, Molecular
D011485 Protein Binding The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments. Plasma Protein Binding Capacity,Binding, Protein
D004655 Emulsions Colloids formed by the combination of two immiscible liquids such as oil and water. Lipid-in-water emulsions are usually liquid, like milk or lotion. Water-in-lipid emulsions tend to be creams. The formation of emulsions may be aided by amphiphatic molecules that surround one component of the system to form MICELLES. Emulsion
D004789 Enzyme Activation Conversion of an inactive form of an enzyme to one possessing metabolic activity. It includes 1, activation by ions (activators); 2, activation by cofactors (coenzymes); and 3, conversion of an enzyme precursor (proenzyme or zymogen) to an active enzyme. Activation, Enzyme,Activations, Enzyme,Enzyme Activations
D005260 Female Females
D006801 Humans Members of the species Homo sapiens. Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D001647 Bile Acids and Salts Steroid acids and salts. The primary bile acids are derived from cholesterol in the liver and usually conjugated with glycine or taurine. The secondary bile acids are further modified by bacteria in the intestine. They play an important role in the digestion and absorption of fat. They have also been used pharmacologically, especially in the treatment of gallstones. Bile Acid,Bile Salt,Bile Salts,Bile Acids,Acid, Bile,Acids, Bile,Salt, Bile,Salts, Bile

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