Abstract

Based on the work of Hynne et al. (2001), in an in silico model of glycolysis,Saccharomyces cerevisiae is established by introducing an enzyme amount multiple factor (É‘) into the kinetic equations. The model is aimed to predict the metabolic response to the change of enzyme amount. With the help of É‘, the amounts of twelve enzymes were altered by different multiples from their initial values. Then twenty metabolite concentrations were monitored and analyzed. The prediction of metabolite levels accord with the experimental result and understanding of bioprocess. It also suggested that the metabolic response to dropping enzyme amounts was stronger than the increasing concentrations. Besides, two different trends of change in the metabolite levels appeared apparently, which are correspond with the network structure. Therefore, for regulating the metabolite levels through changing enzyme amount, not only biochemical characteristic but also location of enzymes in the network should be considered.

Key words: Glycolysis, yeast, metabolites level, enzyme perturbation, kinetic model.

Abbreviation

EtOH, Ethanol; HK, hexokinase; GAPDH, glyceraldehyde-3- phosphate dehydrogenase; ADH, alcohol dehydrogenase; TIM, triose phosphate isomerase; lpGlyc, lumped glycerol formation reaction; PDC, pyruvate decarboxylase; ALD, aldolase; PFK, phosphofructokinase; PK, pyruvate kinase;PGI, phosphoglucose isomerase; lpPEP, phosphoenol pyruvate formation reaction.