Biomaterial Database

The kinetics of hydrolysis of some extended N-aminoacyl-l-lysine methyl esters. 1976

G D Green, and G Tomalin

1. The action of two active forms of bovine trypsin (alpha and beta-trypsin) on a series of specific methyl ester substrates of general formula: N-acetyl-(glycyl)n-L-lysine methyl ester (n = 0, 1, 2) and N2-benzoyl-L-arginine ethyl ester have been investigated. With the L-lysine methyl esters the catalytic rate constant for hydrolysis (kcat) was found to be significantly lower for alpha-trypsin than for beta-trypsin, whereas with N2-benzoyl-L-arginine ethyl ester there was no significant difference for the two enzymes. 2. By measurement of the kinetic constants (kcat and Km) in the presence of a nucleophile, which competes with water in the deacylation process, it has been shown that, in common with the specific ester substrates of trypsin, the rate-determining step for the extended L-lysine methyl esters is decaylation of the enzyme. 3. It has been found that by extending the aminoacyl group of N-acetyl-L-lysine methyl ester by one glycine residue (n = 1), a greatly enhanced deacylation rate constant is observed for both alpha and beta-trypsin. The higher rate constants were maintained at the higher levels by the addition of a further glycine residue (n = 2). These results have been interpreted in terms of the 'induced fit' hypothesis the substrates binding to an enzyme subsite adjacent to the active site. 4. The beta-trypsin-catalysed hydrolysis of the L-lysine substrates was investigated over a range of temperature (15--35 degrees C). The Arrhenius law was obeyed, within experimental error, by all three substrates allowing the estimation of the thermodynamic function of activation (delta S not equal to and deltaH note equal to) for the deacylation reactions. The significantly higher values of deltaS not equal to and deltaH not equal to obtained for the two extended substrates are interpreted in terms of additional hydrogen bonding between the longer aminoacyl chains and the enzyme molecule. The results are compared with those for non-extended specific substrates, which have a possible hydrophobic interaction with the enzyme surface.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D008239	Lysine	An essential amino acid. It is often added to animal feed.	Enisyl,L-Lysine,Lysine Acetate,Lysine Hydrochloride,Acetate, Lysine,L Lysine
D009994	Osmolar Concentration	The concentration of osmotically active particles in solution expressed in terms of osmoles of solute per liter of solution. Osmolality is expressed in terms of osmoles of solute per kilogram of solvent.	Ionic Strength,Osmolality,Osmolarity,Concentration, Osmolar,Concentrations, Osmolar,Ionic Strengths,Osmolalities,Osmolar Concentrations,Osmolarities,Strength, Ionic,Strengths, Ionic
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
D002151	Calorimetry	The measurement of the quantity of heat involved in various processes, such as chemical reactions, changes of state, and formations of solutions, or in the determination of the heat capacities of substances. The fundamental unit of measurement is the joule or the calorie (4.184 joules). (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
D002417	Cattle	Domesticated bovine animals of the genus Bos, usually kept on a farm or ranch and used for the production of meat or dairy products or for heavy labor.	Beef Cow,Bos grunniens,Bos indicus,Bos indicus Cattle,Bos taurus,Cow,Cow, Domestic,Dairy Cow,Holstein Cow,Indicine Cattle,Taurine Cattle,Taurus Cattle,Yak,Zebu,Beef Cows,Bos indicus Cattles,Cattle, Bos indicus,Cattle, Indicine,Cattle, Taurine,Cattle, Taurus,Cattles, Bos indicus,Cattles, Indicine,Cattles, Taurine,Cattles, Taurus,Cow, Beef,Cow, Dairy,Cow, Holstein,Cows,Dairy Cows,Domestic Cow,Domestic Cows,Indicine Cattles,Taurine Cattles,Taurus Cattles,Yaks,Zebus
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
D004952	Esters	Compounds derived from organic or inorganic acids in which at least one hydroxyl group is replaced by an –O-alkyl or another organic group. They can be represented by the structure formula RCOOR’ and are usually formed by the reaction between an acid and an alcohol with elimination of water.	Ester
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D001665	Binding Sites	The parts of a macromolecule that directly participate in its specific combination with another molecule.	Combining Site,Binding Site,Combining Sites,Site, Binding,Site, Combining,Sites, Binding,Sites, Combining