The main objective for the experiment was to employed enzyme kinetics to determine the type of inhibition that methyl- β -D-galactopyranoside (MPG) inhibitor has when reacted with β-galactosidase on substrate o-nitrophenol-β-D-galactoside (ONPG). In the first part of the experiment 5 microtubes containing different volumes of ONPG substrate and phosphate buffer were reacted with β-galactosidase and the absorbance was recorded. The second part of the experiment was just like part I, except that MPG inhibitor was added to the reactions and then once again the absorbance was recorded. After the absorbance was obtained the concentration was determine using Beer Law (A=εcl). After the experiment was completed it was noted that the concentration…show more content… The amount of substrate used was the same as the first part, but the volume of the phosphate buffer was rearranged to make up for the volume of MPG added. Table 4 shows the absorbance of each tube at a wavelength of 420nm, during 3 minutes. The absorbance increases as time increased, and the absorbance decreased as the amount of substrate was descreased. It is noticed that the absorbance readings from table 1 were higher for the reactions without inhibitor in comparison to the absorbance reading from table 4 which had smaller absorbance when reacted with MPG inhibitor. Table 4 shows the calculated concentrations of product made in the presence of MPG inhibitor. As compared to table 1, less concentration of product was made in the presence of MPG inhibitor. For example in table 1 in tube 1 the concentration of product was 0.003mM while in table 4 in tube 1 the concentration of product was 0.021mM when the amount of substrate used was .25mL of ONPG.. Table 3 shows the calculations done without the presence of the inhibitor; this is the same thing performed for table 6. The V0 (mM/min) of the no inhibitor and MPG inhibitor reactions were obtained from the slope of the best fit lines of the graphs in figures 6 and 12. The V0 without inhibitor was greater than the V0 of MPG inhibitor; this shows that the inhibitor was slowing down the reaction between the ONPG and β-galactosidase. Table 6 shows the Lineweaver-Burk plot data, which was derived from the inverse of substrate and V0