In this work, we study the origin of dynamic disorder in a simple reaction network of substrate inhibition and product feedback inhibition loop. It is well established that dynamic disorder arises in a biochemical reaction network not only due to enzymatic fluctuations influencing the catalytic rate but also due to the physical presence of inhibitors owing to their transition between active and inhibited states of enzymes. But we show here, for networks, where there is explicitly no physical presence of an inhibitor but either the reactant or the product in time course of the reaction possesses to be the one. There is a strikingly noticeable dependence of the randomness parameter on the substrate concentration that can discriminate between both the phenomena under consideration. © 2021 Wiley Periodicals LLC