Michaelis-Menten kinetics 3-galactosidase

Catalytic properties of P-galactosidase BGase follows Michaelis-Menten kinetics (Wallenfels and Weil, 1972) and so that Km = Ks. However, additional enzyme complexes may be distinguished ... 

Referring to product concentration in the permeate stream, cytoplasmatic B-galactosidase in cells exhibits an apparent Michaelis-Menten kinetic behaviour,Figure 8. The apparent Michaelis constant increases from 3.7 to 19.2 mM as the pressure increases. Maximum glucose production at 70 °C ranges from 20.4 to 34 moles/hr, at 0.04 and 0.055 atm, respectively. 

Since, as in simple Michaelis-Menten kinetics, the reaction rate depends linearly on the enzyme concentration, the accuracy of activator determinations depends on the precision with which the enzyme concentration is known. Although it is not necessary to employ pure enzymes for the purpose of activator quantification, problems may arise if several isoenzymes exist of which only one is able to degrade the glycolipid substrate in the presence of the activator but all of them hydrolyze the artificial substrates employed for measuring the enzyme. This is, for example, the case for a-galactosidase, p-hexosaminidase, and arylsulfatase. In these cases separation of the isoenzymes, say by ion-exchange chromatography, is required. 

The approach was initially used to describe the inhibition of P-galactosidase by imidazole using a global kinetic data fitting aj>proach (Walsh et al., 2010). The open structure of the expression when comp>ared to integral forms of the Michaelis-Menten equation found in the literature allowed for the insertion of modifier terms in the same way outlined in the previous section (Walsh et al., 2010 Equation 36). 

---