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Examples

Below are a few examples that were used to test the present implementation of the King-Altman method. You may wish to modify the examples, for example by adding activators and/or inhibitors.

Copy text from the editable areas below, and paste it into the data submision page.

IMPORTANT NOTE: All activators and/or inhibitors must be shown in the [modifiers] section (as a comma separate list, if more than one modifier is present).

Examples

Irreversible Michaelis-Menten mechanism
Reversible Michaelis-Menten mechanism
Competitive inhibition
Partial mixed-type noncompetitive inhibition
Botts Morales modifier mechanism
Bi Bi Ordered mechanism
Bi Bi Theorell-Chance mechanism
Bi Uni Random mechanism
Bi Bi Random mechanism
Dihydrofolate reductase
Mixed-type inhibition of dihydrofolate reductase

Irreversible Michaelis-Menten mechanism

The simplest possible enzymatic reaction mechanism:

[reaction] A ---> P [mechanism] E + A <==> ES ES ---> E + P [end]

Reversible Michaelis-Menten mechanism

Fully reversible version of the mechanism above:

[reaction] A <==> P [mechanism] E + A <==> ES ES <==> E + P [end]

Competitive inhibition

Reversible Michaelis-Menten in the presence of a competitive inhibitor:

[reaction] A <==> P [modifiers] I [mechanism] E + A <==> ES ES <==> E + P E + I <==> EI [end]

Partial mixed-type noncompetitive inhibition

The ternary complex Enzyme-Substrate-Inhibitor is partially catalytically active:

[reaction] S <==> P [modifiers] I [mechanism] E + S <==> ES ES <==> E + P E + I <==> EI ES + I <==> ESI ESI <==> EI + P [end]

Botts Morales modifier mechanism

The Botts-Morales general modifier mechanism is a favored system for testing rate equation derivation methods:

[reaction] S <==> P [modifiers] M [mechanism] E + S <==> ES ES <==> E + P E + M <==> EM EM + S <==> EMS ES + M <==> EMS EMS <==> EM + P [end]

Bi Bi Ordered mechanism

Compare the results with Segel's Enzyme Kinetics, page 562 (Equation IX-87):

[reaction] A + B <==> P + Q [mechanism] E + A <==> EA EA + B <==> EXY EXY <==> EQ + P EQ <==> E + Q [end]

Bi Bi Theorell-Chance mechanism

Compare the results with Segel's Enzyme Kinetics, page 594 (Equation IX-122):

[reaction] A + B <==> P + Q [mechanism] E + A <==> EA EA + B <==> EQ + P EQ <==> E + Q [end]

Bi Uni Random mechanism

Compare the results with Segel's Enzyme Kinetics, page 647 (Equation IX-181):

[reaction] A + B <==> P [mechanism] E + A <==> EA E + B <==> EB EA + B <==> EAB EB + A <==> EAB EAB <==> E + P [end]

Bi Bi Random mechanism

Compare the results with Segel's Enzyme Kinetics, page 649: this mechanism should produce 48 denominator terms.

[reaction] A + B <==> P + Q [mechanism] E + A <==> EA EA + B <==> EXY E + B <==> EB EB + A <==> EXY EXY <==> EQ + P EQ <==> E + Q EXY <==> EP + Q EP <==> E + P [end]

Dihydrofolate reductase

Benkovic et al. (1988) painstakingly determined all elementary rate constants in this relatively complex mechanism:

; Dihydrofolate reductase ; Benkovic et al. (1988) Science 239, 1105. ; ; A ... NADPH+ ; B ... dihydrofolate ; P ... NADP ; Q ... tetrahydrofolate ; [reaction] A + B <==> P + Q [mechanism] E + A <==> E.A E + B <==> E.B E + P <==> E.P E + Q <==> E.Q E.A + B <==> E.A.B E.A.B <==> E.P.Q E.P.Q <==> E.Q + P E.Q + A <==> E.Q.A E.Q.A <==> E.A + Q E.B + A <==> E.A.B E.P.Q <==> E.P + Q [end]

Mixed-type inhibition of dihydrofolate reductase

Appleman et al. (1988) determined that certain inhibitors bind both to free dihydrofolate reductase, and to the DHRF-NADPH⁺ complex. This system represents the most complex mechanism in this collection of example problems:

; Inhibition steps: ; Appleman (1988) J. Biol. Chem. 263, 10304. [reaction] A + B <==> P + Q [modifiers] I [mechanism] E + A <==> E.A E + B <==> E.B E + P <==> E.P E + Q <==> E.Q E.A + B <==> E.A.B E.A.B <==> E.P.Q E.P.Q <==> E.Q + P E.Q + A <==> E.Q.A E.Q.A <==> E.A + Q E.B + A <==> E.A.B E.P.Q <==> E.P + Q E.A + I <==> E.A.I E + I <==> E.I [end]