function [k1]=bindingconst(C_cai)
% k1=0.35*(t>=0 & t<=5)+ 0.06*(t>5);
% k6=0.35*(t>=0 & t<=5)+ 0.06*(t>5);
n = 8.7613;
Ca_mlck = 256.98;
k1 = (C_cai.^n)/((Ca_mlck.^n)+(C_cai.^n));
