The study of efficient methods to deduce fluxes of biological reactions, by starting from experimental data, is necessary to understand metabolic dynamics, and is a central issue in systems biology. In this paper we report some initial results, together with related open problems, regarding the efficient computation of regulation fluxes in metabolic P systems. By means of Log-gain theory the system dynamics can be linearized, in such a way to be described by a recurrence equations system, of which we point out a few algebraic properties, involving covering problems.