“…Such an autoregulation mechanism (where the gene product auto-regulates its own gene expression) is very common in living cells, which occurs over 40% of known E. coli's transcription factors [49]. Moreover, it has various biological functions, including speeding up the response time of gene expression [50], inducing genetic oscillators [51], and achieving adaptation to periodic external stimuli [52]. The model considered in this subsection involves five species: the protein monomer (denoted by S 1 ), the dimer (also the transcription factor, denoted by S 2 ), the mRNA (S 3 ), the unbound DNA (S 4 ), and the bound DNA (also the activated state, denoted by S 5 ); moreover, it has eight reactions:…”