91影视

The reciprocal of the substrate concentration and initial velocity are used to construct the Lineweaver-Burk plot.

The resulting graph is a linear line, with the X-intercept and Y-intercept extrapolated until the X-axis. The initial velocity with and without the inhibitor is shown on the Y-axis and the substrate concentration on the X-axis.

In the absence of an inhibitor,

$$\begin{gathered} {\mathrm{K}}_{\mathrm{M}}=\frac{-1}{\mathrm{x}\mathrm{intercept}} \\ =\frac{-1}{0.14{\mathrm{渭惭}}^{-1}} \\ =7.1\mathrm{渭惭} \end{gathered}$$

$$\begin{gathered} {\text{V}}_{\text{max}}\text{=}\frac{\text{- 1}}{\text{y}鈥�\text{intercept}} \\ 鈥�鈥�鈥�鈥�鈥�鈥�鈥�鈥�鈥�\text{=}\frac{\text{- 1}}{{\text{- 0.008mg}}^{\text{- 1}}\text{min}} \\ 鈥�鈥�鈥�鈥�鈥�鈥�鈥�鈥�鈥�\text{= 125mg}鈥�{\text{min}}^{\text{- 1}} \end{gathered}$$

In the presence of an inhibitor,

$$\begin{gathered} {{\mathrm{K}}_{\mathrm{M}}}^{\mathrm{app}}=\frac{-1}{\mathrm{x}\mathrm{intercept}} \\ =\frac{-1}{-0.04{\mathrm{渭惭}}^{-1}} \\ =25\mathrm{渭惭} \end{gathered}$$

$$\begin{gathered} {\text{V}}_{\text{max}}^{\text{app}}\text{=}\frac{\text{- 1}}{\text{y}鈥�\text{intercept}} \\ 鈥�鈥�鈥�鈥�鈥�鈥�鈥�鈥�鈥�\text{=}\frac{\text{- 1}}{{\text{0.01mg}}^{\text{- 1}}\text{min}} \\ 鈥�鈥�鈥�鈥�鈥�鈥�鈥�鈥�鈥�\text{= 100mg}鈥�{\text{min}}^{\text{- 1}} \end{gathered}$$

A competitive inhibitor refers to a chemical substance or a molecule that competes with the substrate for the active site of the enzyme. The 1/v₀ axis is extremely close to the intersection of the lines in the Lineweaver-Burk plot. This indicates that threo-sphingosine is a competitive inhibitor.

Moreover, threo-sphingosine and sphingosine have a structural resemblance, implying that they would likely compete for the enzyme's substrate-binding site (active site), supporting the result of the graph.