Active transporter change in concentration

[akim2000]

I was trying to create an active transport process from the brain plasma into the brain interstitial space.

This is what I have so far and it seems to be transporting. For active transport molecules (TMEM30A) in this case, do you need to have a synthesis process going on or does the active transporter not actually get "used up?" I was wondering this, as the graph seemed to plateau after a bit, making be think that I might need to create a synthesis process:

Since I'm simplifying this active transport process into a one-step process of taking the drug from the plasma to the interstitial space (via a rate parameter) and not actually internalizing the vesicle first, I know I could probably just create a passive transport instead, but I wanted to at least use the built-in active transporter in MoBi. Would it be easier if I just create my active transport process as a "passive transport"?