Function of Diferential Ecuations

What happens is that I'm working with a model of Proteins G (the one found in the attached PDF 3.3) and I try to make the program with a function where I include the differential equations that come in the example, but when trying of running the script the graphs are not similar to those of the document, they believe that the function is incorrect or the execution that I am giving. The codes are the following:

Function:

function dydx = examenisb (x,y)

ki = 1; ku = 1; global Km1; global Km2;

V1 = y(2)*ki*x(1)/(Km1+y(2)); V2 = y(1)*ku*x(1)/(Km2+y(1));

dadx = V1-V2; dbdx = -V1-V2; dydx = [dadx -dbdx]'; %%%%

Script:

global Km1; global Km2; Km1=.001; Km2=.001; [x,y]=ode45(@examenisb,[0,2],[0.1 0.1]); plot(x,y);

xlabel('tiempo (h)') ylabel('biomasa') title('Biomasa')