The process of turning a doctoral student into an independent researcher is usually guided by a professor. In this work, the supervisor-supervisee relationship is represented by a scheme inspired by Michaelis-Menten kinetics, which has been used to determine the rate of enzyme-catalysed reactions. Here, the time evolution of the number of supervisors with "k" supervisees is modelled by a system of linear ordinary differential equations. The long-term behaviour of these equations is analytically examined and illustrated by a numerical simulation. This model related to the PhD formation catalysed by a professor can be presented in a class on differential equations or chemical kinetics.