Function code

function dy=ty_enzymekinetics(t,y)

%%

global k1 k2 k3

%%

%equations

%dEdt = -k1*E*S + k3*ES + K2*ES;

dy(1)= -k1*y(1)*y(2) + k3*y(3)+k2*y(3);

%dSdt = k2*ES - k1*E*S;

dy(2) = k2*y(3) - k1*y(1)*y(2);

%dESdt = -k3*ES - k2*ES + k1*E*S;

dy(3) = -k3*y(3) - k2*y(3) + k1*y(1)*y(2);

%dPdt = k3*ES;

dy(4) = k3*y(3);

dy = [dy(1);dy(2);dy(3);dy(4)];

Calling code

%function call

clear all;

clc;

%%

global k1 k2 k3

%k1 = 10;

k2 = 1;

k3 = 1;

i=1;

for k1=1:1:5

[T,Y]=ode45(@ty_enzymekinetics,[0:0.01:2], [10 10 0 0]);

A1(:,i) = Y(:,1); %enzyme conc

A2(:,i) = Y(:,2); %substrate conc

A3(:,i) = Y(:,3); %ES complex conc

A4(:,i) = Y(:,4); %product conc

i=i+1;

end

subplot(1,4,1);plot(T,A1); TITLE('Enzyme kinetics');xlabel('time');ylabel('enzyme');legend('k1=1','k1=2','k1=3','k1=4','k1=5'); %plotting [E]

subplot(1,4,2);plot(T,A2); TITLE('Enzyme kinetics');xlabel('time');ylabel('substrate');legend('k1=1','k1=2','k1=3','k1=4','k1=5');%plotting [S]

subplot(1,4,3);plot(T,A3); TITLE('Enzyme kinetics');xlabel('time');ylabel('complex'); legend('k1=1','k1=2','k1=3','k1=4','k1=5');%plotting [ES]

subplot(1,4,4);plot(T,A4); TITLE('Enzyme kinetics');xlabel('time');ylabel('product');legend('k1=1','k1=2','k1=3','k1=4','k1=5'); %plotting [P]