Kinetics of enzymatic synthesis of isopropylidene glycerol esters by goat pregastric lipase

Abstract

The goat pregastric lipase-catalyzed esterification of isopropylidene glycerol with caproic acid, to form isopropylidene glycerol caproate, followed a ping pong bi bi mechanism incorporating an acyl-enzyme intermediate. The maximum rate was estimated to be 96 µmol min -1 mg -1 in isooctane at 35°C, and the Michaelis-Menten constants for isopropylidene glycerol and caproic acid were 0.23 and 0.32 M, respectively. The catalyzed rate also correlated well with the partition coefficient of caproic acid between the organic and aqueous phases. The results suggest that the desolvation energy of the substrate from the bulk medium to the active site of the enzyme dominates the reaction rate for the enzyme-catalyzed reaction in organic media.Paper no. J9049 in JAOCS 76, 845-851 (July 1999).

Effect of Chain Length on Enzymatic Hydrolysis of p-Nitrophenyl Esters in Supercritical Carbon Dioxide

“…In this type of reaction, involving two substrates and two products (Bi Bi reaction), the enzyme reacts with the first substrate to give a covalently modified enzyme intermediate and then releases the second product (Ping Pong mechanism). Several other studies confirmed that experimental data for hydrolysis, esterification, alcoholysis, and ester exchange reactions catalyzed by lipases in various organic solvents were well fitted by this model [48][49][50][51][52][53][54]. In most cases, competitive inhibition by the alcohol was reported.…”

Enzymatic Kinetics of Fatty Acids Methyl Ester from Kapok Seed Oil (Ceiba Petandra) Using Lipozyme TL IM

“…However, the enzymatic catalysis of the two substrates could be controlling concentration of one of the substrates. This results in the formation of a plot following Michelis-Menten relationship between the initial rate and the other substrate concentration (Lai et al, 1999). Michaelis and Menten provided an explanation regarding a mechanism of "the initial rate of enzyme-catalyzed reactions" that is highly affected by the concentration.…”

Enzyme–Catalysed Synthesis of Palm-Based Wax Esters-A Kinetic Study

“…Given the nature of enzyme-catalyzed reactions, the case of a single product reaction is very rare. Most cases of enzyme-catalyzed reactions involve more than one substrate and produce two or more products (Lai et al 1999). The alcoholysis of palm oil with oleyl alcohol can be considered in this research as an enzymatic reaction system, which involves two reactants and two products.…”

“…Based on the type of substrates, the most appropriate explanation for the lipase catalysis mechanism is ping-pong mechanism and ordered bi-bi mechanism, which involve acyl-enzyme intermediate. Lai et al (1999), combine these mechanisms to be pingpong bi-bi (i.e., bi-substrate, bi-product, non-sequential kinetics) mechanism, in which the first reactant would be involved in the reaction mechanism producing the max max (acyl migration processes) are the lowest rate constants of the whole catalytic process. In other words, acyl migration is the rate-determining step.…”

“…Although this behavior would be expected for the chemical equilibrium of the species, the decrease observed indicates the possibility of inhibition effects due to the concentration of both species on the catalytic function of the enzyme (Zaidi et al 2002).Interpretation of the kinetics of most enzyme-catalyzed synthetic reactions is hampered because the behavior Initial reaction rate of alcoholysis as a function of palm oil concentration(OA = Oleyl alcohol, V 0 = initial rate) Initial reaction rate of palm oil (PO) alcoholysis as a function of oleyl alcohol concentration (V 0 = initial rate) predicted by a mathematical formula is only valid in an ideal system in which the concentration of both substrates is small. However, the enzymatic catalysis of two substrates can be simplified by maintaining the concentration of one substrate, and a plot of initial rate against the other substrate concentration will follow a Michaelis-Menten type relationship(Lai et al 1999).The maximum initial rate of substrates consumption(v max ) and Michaelis-Menten constants (K m ) were determined by linear regression using the Lineweaver-Burk approach. The v max and K m are two important kinetic parameters, which are useful for describing the properties of an enzyme-catalyzed reaction.…”