Pattern formation in an immobilized bienzyme system. A morphogenetic model

S. Cortassa, H. Sun, J. P. Kernevez, D. Thomas

Research output: Contribution to journalArticle

Abstract

Experimental and theoretical studies of a reaction-diffusion model of two immobilized enzymes participating in the cellular acid-base metabolism, namely glutaminase and urease, are presented. The system shows an unstable steady state at pH 6.0, where any perturbation will drive the system towards a more alkaline or more acidic pH, owing to the autocatalytic behaviour with respect to pH exhibited by both enzymes. When diffusion is coupled to reaction by means of immobilization, different patterns of the internal pH profile appear across the membrane. If the bienzymic membrane is subjected to a perturbation at its boundaries, at the same amplitude but in opposite directions, the internal pH evolves through an asymmetric pattern to attain a nearly symmetric distribution of pH. The pH value at the final steady state is more acidic or more alkaline than the initial state according to the initial and boundary conditions. The final nearly symmetric state is attained more rapidly when less enzyme is immobilized (1.8 x 10-4 M·s-1 as against 3.3 x 10-4 M·s-1 of total enzyme activity in the membrane volume). The experimental results agree rather well qualitatively with numerical predictions of the model equations.

Original languageEnglish (US)
Pages (from-to)115-122
Number of pages8
JournalBiochemical Journal
Volume269
Issue number1
StatePublished - 1990
Externally publishedYes

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Membranes
Glutaminase
Immobilized Enzymes
Urease
Enzyme activity
Enzymes
Metabolism
Boundary conditions
Acids
Immobilization
Theoretical Models
Direction compound

ASJC Scopus subject areas

  • Biochemistry

Cite this

Cortassa, S., Sun, H., Kernevez, J. P., & Thomas, D. (1990). Pattern formation in an immobilized bienzyme system. A morphogenetic model. Biochemical Journal, 269(1), 115-122.

Pattern formation in an immobilized bienzyme system. A morphogenetic model. / Cortassa, S.; Sun, H.; Kernevez, J. P.; Thomas, D.

In: Biochemical Journal, Vol. 269, No. 1, 1990, p. 115-122.

Research output: Contribution to journalArticle

Cortassa, S, Sun, H, Kernevez, JP & Thomas, D 1990, 'Pattern formation in an immobilized bienzyme system. A morphogenetic model', Biochemical Journal, vol. 269, no. 1, pp. 115-122.
Cortassa S, Sun H, Kernevez JP, Thomas D. Pattern formation in an immobilized bienzyme system. A morphogenetic model. Biochemical Journal. 1990;269(1):115-122.
Cortassa, S. ; Sun, H. ; Kernevez, J. P. ; Thomas, D. / Pattern formation in an immobilized bienzyme system. A morphogenetic model. In: Biochemical Journal. 1990 ; Vol. 269, No. 1. pp. 115-122.
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