Advances in genetic manipulation have allowed the overexpression of proteins and insertion of circuits in cells. However, the expected behaviour can be altered by the internal competition for the limited amount of cellular resources. In this work we analyse a feedback strategy based on transcription inhibition that aims to reduce the interaction in a two-protein expression system. The results allow interpreting the effects of negative feedback on the steady-state protein levels and how the realizable protein region is affected by the feedback loop.