Justification-2 Enzyme Inhibition: Lineweaver-Burk
(Justification-2 Enzyme Inhibition)
By quantitative balance, the total amount of Enzyme is [E] 0= [E] + [EI] + [ES] + [ESI].
By using a=1+[I]/KI and a′=1+[I]/K′I, it is followed by [E]0=[E]a+[ES]a′
This equation can be written like this, [E]0=(Km[ES])/([S]0)a + [ES]a′=[ES]( aKm/[S}0+a'), because of Km=[E][S]/[ES] and [S]≈[S]0.
V=kb [ES] =kb [E] 0/ (aKm/[s] 0+a'). Kb [E] 0 is Vmax. This is why V=Vmax/(a^'+aKm/[S]0).
This equation can be rearranged like this, 1/V= a'/Vmax+(aKm/Vmax)1/[S]0, which is the Lineweaver-Burk plots.
Inhibition mode Competitive Uncompetitive Noncompetitive
The Lineweaver-Burk plot.
(Fig 9) The Lineweaver-Burk plots The enzyme inhibition can be explained by Gibbs energy. At the standard state, which is [E]= …show more content…
This is can be plotted at the graph. (Fig 10) Standard Gibbs energy profile
The standard state Gibbs energy can be changed following the variation of concentration of inhibitors.
[E]I denotes the concentration of enzyme when competitive inhibitor exists. [E]I= [E]-[EI]
KI= [E]i[I]/[EI]
[E]I= [E]- ([E]i[I])/KI
[E]I= [E]/a (a=1+ [I]/KI)
The Gibbs energy change of substrates is followed by
∆Gs′= ∆Gs°′-RTln([E]i[I]/[EI] )
∆Gs′= ∆Gs°′-RTln([E][I]/[EI] )/a
∆Gs′= ∆Gs°′+RTlna. (This is because at the standard state [E] = [S] = [ES] =1 M)
[ES]I is the concentration of the enzyme-substrate complex when uncompetitive inhibitors exist. At that time, [ES] I = [ES]-[ESI]
Following with this,
KI′=[ES]i[I]/[ESI]
[ES]I= [ES]- [ES]i[I]/Ki
[ES]I =[ES]/a′ (a′=1+[I]/K′I)
∆Gs′= ∆Gs°′-RTln {([E][I]/[ES]i)}
∆Gs′= ∆Gs°′- RTln {([E][I]/[ES] )a'}
∆Gs′= ∆Gs°′- RTlna′(this is because at the standard state, [ES]= [E]= [S])
When noncompetitive inhibitor exists, the [ES] I and [E] I are same value mentioned above. Also, the value of a is equal to a′.
Following with this,
∆Gs′= ∆Gs°′-RT{([E]i[I]/[ES]i)}
∆Gs′= ∆Gs°′-RT{(([E][I]/[ES] …show more content…
For instances, inhibition of calystegines can be one method of dealing with the diabetes mellitus type 2. The difference between type 1 and type 2 is type 2 diabetes develops slowly. It is following the pre-diabetes status such as obesity, high blood pressure, and increased blood glucose level after the meal because of less insulin sensitivity. For these patients, glucosidase inhibitors like acarbose and miglitol, which inhibit maltase and sucrose, are applied as medicine. Also, calystegines A3 and B2 from potatoes can play a role in inhibitors for maltase and sucrase. (Fig 12) the structures of substrates and inhibitors
At the Caco-2 cell, the inhibition of sucrase and maltase by calystegines A3 and B2 give us this result. Maltase Sucrase Vmax[pkat/mg] Km[mM] R2 KI[µM] Vmax[pkat/mg] Km[mM] R2 KI[µM]
No inhibitor 827±12 7.3±0.5 0.9938 412±23 11.1±2.5 0.9570
Acarbose 5µM 725±12 15.6±0.8 0.9980 4.4 166±11 18.2±3.9 0.9678 7.8 calystegines A3 476µM 939±23 11.1±1.1 0.9913 d 298±7 12.5±1.1 0.9939 227±47
Calystegines B2 476µM 1016±22 25.4±1.5 0.9980 582±144 236±8 25.4±2.3 0.9948 55±12
(Fig 13) Maltase and sucrase inhibition by calystegines A3 and
By quantitative balance, the total amount of Enzyme is [E] 0= [E] + [EI] + [ES] + [ESI].
By using a=1+[I]/KI and a′=1+[I]/K′I, it is followed by [E]0=[E]a+[ES]a′
This equation can be written like this, [E]0=(Km[ES])/([S]0)a + [ES]a′=[ES]( aKm/[S}0+a'), because of Km=[E][S]/[ES] and [S]≈[S]0.
V=kb [ES] =kb [E] 0/ (aKm/[s] 0+a'). Kb [E] 0 is Vmax. This is why V=Vmax/(a^'+aKm/[S]0).
This equation can be rearranged like this, 1/V= a'/Vmax+(aKm/Vmax)1/[S]0, which is the Lineweaver-Burk plots.
Inhibition mode Competitive Uncompetitive Noncompetitive
The Lineweaver-Burk plot.
(Fig 9) The Lineweaver-Burk plots The enzyme inhibition can be explained by Gibbs energy. At the standard state, which is [E]= …show more content…
This is can be plotted at the graph. (Fig 10) Standard Gibbs energy profile
The standard state Gibbs energy can be changed following the variation of concentration of inhibitors.
[E]I denotes the concentration of enzyme when competitive inhibitor exists. [E]I= [E]-[EI]
KI= [E]i[I]/[EI]
[E]I= [E]- ([E]i[I])/KI
[E]I= [E]/a (a=1+ [I]/KI)
The Gibbs energy change of substrates is followed by
∆Gs′= ∆Gs°′-RTln([E]i[I]/[EI] )
∆Gs′= ∆Gs°′-RTln([E][I]/[EI] )/a
∆Gs′= ∆Gs°′+RTlna. (This is because at the standard state [E] = [S] = [ES] =1 M)
[ES]I is the concentration of the enzyme-substrate complex when uncompetitive inhibitors exist. At that time, [ES] I = [ES]-[ESI]
Following with this,
KI′=[ES]i[I]/[ESI]
[ES]I= [ES]- [ES]i[I]/Ki
[ES]I =[ES]/a′ (a′=1+[I]/K′I)
∆Gs′= ∆Gs°′-RTln {([E][I]/[ES]i)}
∆Gs′= ∆Gs°′- RTln {([E][I]/[ES] )a'}
∆Gs′= ∆Gs°′- RTlna′(this is because at the standard state, [ES]= [E]= [S])
When noncompetitive inhibitor exists, the [ES] I and [E] I are same value mentioned above. Also, the value of a is equal to a′.
Following with this,
∆Gs′= ∆Gs°′-RT{([E]i[I]/[ES]i)}
∆Gs′= ∆Gs°′-RT{(([E][I]/[ES] …show more content…
For instances, inhibition of calystegines can be one method of dealing with the diabetes mellitus type 2. The difference between type 1 and type 2 is type 2 diabetes develops slowly. It is following the pre-diabetes status such as obesity, high blood pressure, and increased blood glucose level after the meal because of less insulin sensitivity. For these patients, glucosidase inhibitors like acarbose and miglitol, which inhibit maltase and sucrose, are applied as medicine. Also, calystegines A3 and B2 from potatoes can play a role in inhibitors for maltase and sucrase. (Fig 12) the structures of substrates and inhibitors
At the Caco-2 cell, the inhibition of sucrase and maltase by calystegines A3 and B2 give us this result. Maltase Sucrase Vmax[pkat/mg] Km[mM] R2 KI[µM] Vmax[pkat/mg] Km[mM] R2 KI[µM]
No inhibitor 827±12 7.3±0.5 0.9938 412±23 11.1±2.5 0.9570
Acarbose 5µM 725±12 15.6±0.8 0.9980 4.4 166±11 18.2±3.9 0.9678 7.8 calystegines A3 476µM 939±23 11.1±1.1 0.9913 d 298±7 12.5±1.1 0.9939 227±47
Calystegines B2 476µM 1016±22 25.4±1.5 0.9980 582±144 236±8 25.4±2.3 0.9948 55±12
(Fig 13) Maltase and sucrase inhibition by calystegines A3 and