Nucleosid diphosphate kinase
Nucleoside-diphosphate kinases are enzymes that catalyze the exchange of phosphate groups between different nucleotides. The overall effect of NDKs is to transfer a phosphate group from a nucleoside triphosphate to a nucleoside diphosphate. Starting with ATP and UDP, the activity of NDK produces ADP and UTP.
Contents
Chemical equation
Rate equation
Random order Bi-Bi rate law is used from [1]
Parameter values
- A mean body weight is defined as 75Kg in Konig et. al [1]. The is calculated by multiplying the reported value with body weight.
Parameter | Value | Units | Organism | Remarks |
---|---|---|---|---|
[2] | Human Liver | |||
[3] | mM | Rat liver | ||
[3] | mM | Rat liver | ||
[4] | mM | Rat tissue | ||
[3] | mM | Rat liver | ||
Dimensionless |
Parameters with uncertainty
- In the paper by Walter (1980) et. al. [3] two values of , and have been reported; one for cytosolic kinase and the other for membrane-associated kinase. As in our model we are not differentiating between cytosolic and membrane-associated kinase, we would consider both those values and calculate the uncertainty from them.
- Similarly two values of has been reported in Fukuchi (1994) et. al. [4]; for kinase and kinase. Taking average of those kinase gives a value of
- Two values of is also reported in Fukuchi (1994) et. al. [4]; 126 (4.20 multiplied with 30 mg) and 138 (4.60 multiplied with 30 mg) . Taking average gives .
- Standard free energy is reported to be zero kJ/mol. Therefore the value of Keq is assumed to be constant.
Parameter | Value | Units | Organism | Remarks |
---|---|---|---|---|
Rat lever | ||||
mM | ||||
mM | ||||
mM | ||||
mM | ||||
Dimensionless |
References
- ↑ 1.0 1.1 M. König, S. Bulik, H.G. Holzhütter (2012), Quantifying the contribution of the liver to glucose homeostasis: a detailed kinetic model of human hepatic glucose metabolism, PLoS Comput. Biol., 8 (6), p. e1002577
- ↑ Villar-Palasi C & Larner J (1960). Levels of activity of the enzymes of the glycogen cycle in rat tissues. Arch Biochem Biophys 86, 270–273.
- ↑ 3.0 3.1 3.2 3.3 Walter P and Blobel G. (1980), Purification of a membrane-associated protein complex required for protein translocation across the endoplasmic reticulum, Proc. Natl. Acad. Sci. 77:7112-7116
- ↑ 4.0 4.1 4.2 Fukuchi, T., Shimada, N., Hanai, N., Ishikawa, N., Watanabe, K., and Kimura, N. (1994) Recombinant rat nucleoside diphosphate kinase isoforms ( and ): purification, properties and application to immunological detection of native isoforms in rat tissues. Biochim. Biophys. Acta 1205, 113–122