External factors involved in the regulation of an extracellular proteinase synthesis in Bacillus megaterium

Research paper by Jaroslav Votruba, Jarmila Pazlarová, Milada Dvořáková, Kalju Vanatalu, Libuše Váchová, Marie Strnadová, Helena Kučerová, Jiří Chaloupka

Indexed on: 01 Jul '87Published on: 01 Jul '87Published in: Applied Microbiology and Biotechnology


A mathematical model was formulated to describe the kinetics and stoichiometry of growth and proteinase production in Bacillus megaterium. Synthesis of the extracellular proteinase in a batch culture is repressed by amino acids. The specific rate of formation of the enzyme (rE) can be described by the formula {ie373-1}, where k2 and k3 stand for the non-repressible and repressible part of enzyme synthesis respectively, kS2 is a repression coefficient and S2 indicates the concentration of amono acids; the values of k2 and kS2 depend on the composition of the mixture of amino acids. Even in a high concentration, a single amino acid is less effective than a mixture of amino acids. The dependence of the proteinase repression on the concentration of an external amino acid (leucine) follows the same course as its rate of incorporation into proteins, approaching saturation at concentrations higher than 50 μM (half saturation approximately 10 μM). However, the total uptake of leucine did not exhibit any saturation even at 500 μM external concentration.