Publication Date:
2017
abstract:
A metabolic pathway made of a cascade of biochemical
reactions is considered, with a substrate which is eventually
transformed into the final product by means of a sequence of
reactions, each catalyzed by the same enzyme. The amount of
the enzyme varies according to discrete noisy processes of production
and elimination. A feedback acts on the final product
clearance rate, exerted by the final product accumulation itself:
higher final product levels lead to a faster dynamics. The aim of
this note is to investigate how the noise scales with the length
of the cascade and how the feedback impacts on the noise
propagation. To this end, a Stochastic Hybrid System (SHS)
formulation is exploited, with the enzyme production/clearance
processes constituting the noise source. The noise propagation is
measured in terms of the square of the coefficient of variation of
the final product, and computations are carried out by means of
the equations of moments, which are estimated in closed form
after linearizing the SHS. Analytical solutions allow to infer
information and to relate the noise propagation to the model
parameters. Similarly to recent results occurring in other types
of enzymatic reactions, the results highlight the influential role
of feedback in noise reduction
Iris type:
04.01 Contributo in Atti di convegno
Keywords:
metabolic pathways; Moment equations; Negative Feedback
List of contributors: