Bernard Korzeniewski

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A dynamic computer model of oxidative phosphorylation in oxidative mammalian skeletal muscle was developed. The previously published model of oxidative phosphorylation in isolated skeletal muscle mitochondria was extended by incorporation of the creatine kinase system (creatine kinase plus phosphocreatine/creatine pair), cytosolic proton(More)
The dynamic computer model of oxidative phosphorylation developed previously and successfully tested for large-scale changes in fluxes and metabolite concentrations was used to study the question of how the rate of ATP production by oxidative phosphorylation is adjusted to meet the energy demand during muscle contraction, which causes a great increase in(More)
1. The dynamic model of oxidative phosphorylation developed previously for rat liver mitochondria incubated with succinate was adapted for muscle mitochondria respiring on pyruvate. We introduced the following changes considering: (1) a higher external ATP/ADP ratio and an ATP/ADP carrier less displaced from equilibrium; (2) a substrate dehydrogenation more(More)
The theoretical studies on the regulation of oxidative phosphorylation that were performed with the aid of kinetic models of this process are overviewed. A definition of the regulation of the flux through a metabolic pathway is proposed and opposed to the control exerted by particular enzymes over this flux. Different kinetic models of oxidative(More)
A definition of life (a living individual) in cybernetic terms is proposed. In this formulation, life (a living individual) is defined as a network of inferior negative feedbacks (regulatory mechanisms) subordinated to (being at service of) a superior positive feedback (potential of expansion). It is suggested that this definition is the minimal definition,(More)
The presented model based on an earlier one (Korzeniewski, B. and Froncisz, W. (1989) Studia Biophys. 132, 173-187) simulates concentration changes in time of chemical compounds and thermodynamic forces during respiration of cell suspension in a closed chamber. A set of differential equations solved numerically describes the utilization of oxygen up to(More)
The mathematical dynamic model of oxidative phosphorylation developed previously and in the accompanying paper was modified to involve isolated mitochondria conditions; it was also used to simulate state 4 --> state 3 transition in rat liver mitochondria incubated with succinate as respiratory substrate and glucose-hexokinase as an ADP-regenerating system.(More)
The glutamate-dependent respiration of isolated BM (brain mitochondria) is regulated by Ca2+(cyt) (cytosolic Ca2+) (S0.5=225±22 nM) through its effects on aralar. We now also demonstrate that the α-glycerophosphate-dependent respiration is controlled by Ca2+(cyt) (S0.5=60±10 nM). At higher Ca2+(cyt) (>600 nM), BM accumulate Ca2+ which enhances the rate of(More)
It is well known that the oxygen uptake kinetics during rest-to-work transition (V(O2) on-kinetics) in trained subjects is significantly faster than in untrained individuals. It was recently postulated that the main system variable that determines the transition time (t(1/2)) of the V(O2) on-kinetics in skeletal muscle, at a given moderate ATP usage/work(More)
In the present debating paper, the problem how the rate of ATP supply by oxidative phosphorylation in mitochondria is adjusted to meet a greatly increased demand for ATP during intensive exercise of skeletal muscle is discussed. Different experimental results are collected from different positions of the literature and confronted with five conceptual models(More)