engleski

A linear cascade reaction for the (re-)generation of coenzyme ATP

Many oxidoreductases, as well as ligases, require coenzymes (e.g. NAD+/NADH, NADP+/NADPH, ATP) for their catalytic function [1]. Although these enzymes represent many of the most useful biocatalysts, their application can be severely limited due to high cost of the coenzymes. Therefore, it is necessary to establish suitable and efficient regeneration systems for these coenzymes. Adenosine-5’-triphosphate (ATP) is one of the essential molecules in living systems. Generally, ATP is used by all classes of enzymes. It can mainly be regarded as a group transfer cofactor in enzymatic reactions and is involved in a tremendous number of diverse biological processes [2]. In this work a linear cascade reaction for the (re-)generation of coenzyme ATP starting from adenosine was studied [3]. The system consists of initial phosphorylation of adenosine catalyzed by adenosine kinase using ATP as phosphate donor and the phosphorylation of AMP and ADP with polyphosphate kinase 2 enzymes and polyphosphate (Scheme 1). Two different polyphosphate kinase 2 enzymes were used for AMP and ADP phosphorylation. Kinetic characterization of all three enzymes involved in the system was carried out to develop a mathematical model of this reaction. Once developed, a mathematical model of this cascade reaction will be used to improve a key parameter for cofactor-dependent enzymes, the total turnover number (TTN) which indicates the moles of product formed per mole of cofactor during its entire life and represents a measure for catalytic efficacy.

ATP, cascade reaction, kinetics, mathematical model

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