KINETIC pmp {
~ cabulk <-> cam (1/tau, 1/tau)
~ cam + pump <-> capump (k1, k2)
~ capump <-> cao + pump (k3, k4)
ica_pmp = 2*FARADAY*(f_flux - b_flux)
~ cam << -(ica) : there is a problem here
COMPARTMENT width {cam} : volume in (um)
COMPARTMENT 1 {pump capump} : area is dimensionless
COMPARTMENT 1(m) {cao cabulk}
}