In this research, Michaelis-Menten kinetic (Michaelis-Menten constant
(Km) and maximum uptake rate (Imax)) provides a useful tool for the identification of plant nutrient uptake efficiency and selection of plants.
The Michaelis-Menten constant
is important to characterize the enzyme electrode due to the character of the aforementioned constant (KM).
Theoretical maximal reaction velocities (Vmax) and Michaelis-Menten constant
(Km) were calculated against CMC using Lineweaver-Bulk plot (Table 1).
where V, [V.sub.max], [K.sub.m], and [S] are reaction rate, maximum reaction rate, Michaelis-Menten constant
, and substrate concentration, respectively.
where Ki refers to inhibition constant; IC50 refers to concentration of fluorinated bile acid that causes a 50% decrease in [sup.3]H labeled substrate uptake; [S] refers to concentration of [sup.3]H labeled substrate; Km refers to Michaelis-Menten constant
of [sup.3]H labeled substrate
The apparent Michaelis-Menten constant
([K.sub.m]), an indicator of enzyme-substrate reaction kinetics, can be used to evaluate the biological activity of the immobilized enzyme, and this constant can be calculated from the Lineweaver-Burk equation, given below:
In , the presented model was derived from the work of diffusion in a punctual iontophoretic source where the lineal term of absorption is replaced by a nonlinear expression that describes a Michaelis-Menten kinetic given by a constant [V.sub.m], the Michaelis-Menten constant
where [I.sub.peak,c] is the peak current at the substrate concentration C, [I.sub.peak,max] is the peak current at saturating substrate conditions, and [K.sup.app.sub.m,el], is a constant with the same meaning as the Michaelis-Menten constant
We use Michaelis-Menten kinetics in order to have a mixed-order model for the pharmacokinetics, so this equation results in the term [[??].sub.3] = -c[x.sub.3]/([K.sub.B] + [x.sub.3]), where the parameter [K.sub.B] is the Michaelis-Menten constant
of the inhibitor;
Abbreviations: CEC, 3-cyano-7-ethoxycoumarin; CYP, cytochrome P450; DMSO, dimethylsulfoxide; [K.sub.m], Michaelis-Menten constant
; Vmax, maximum velocity; [IC.sub.50], the half maximal (50%) inhibitory concentration; [K.sub.i], the inhibitor concentration required for a half-maximal inhibition; NADPH, nicotinamide adenine dinucleotide phosphate.
In order to determine the maximum velocity (Vmax) and Michaelis-Menten constant
(Km) of the glutaminase enzyme we plotted Lineweaver-Burk graph (Fig.
Table 2 shows the Michaelis-Menten constant
(Km,app) and maximal velocity (Vmax,app) of the enzyme in hydrolyzing three different substrates; ATC, BTC and PTC.