Difference between revisions of "Glycogen phosphorylase"
(→Parameters with uncertainty) |
(→Parameters with uncertainty) |
||
Line 236: | Line 236: | ||
|- | |- | ||
|<math>K_{Pi}</math> | |<math>K_{Pi}</math> | ||
− | |4 <ref name=" | + | |<math>4 \pm 0.8</math> <ref name="Gold_1970">Gold, A. M., R. M. Johnson, and J. K. Tseng (1970), ''Kinetic mechanism of rabbit muscle glycogen phosphorylase a'',J. Biol. Chem. 245:2564 –2572, 1970</ref> |
|mM | |mM | ||
|- | |- | ||
|<math>K_{Glyb}</math> | |<math>K_{Glyb}</math> | ||
− | |0.15 <ref name=" | + | |<math>0.15 \pm 0.03</math><ref name="Gold_1970"></ref> |
|mM | |mM | ||
|- | |- | ||
|<math>K_{iGlc1P}</math> | |<math>K_{iGlc1P}</math> | ||
− | |10.1 <ref name=" | + | |<math>10.1 \pm 2.5 </math><ref name="Gold_1970"></ref> |
|mM | |mM | ||
|- | |- | ||
|<math>K_{iPi}</math> | |<math>K_{iPi}</math> | ||
− | |4.6 <ref name=" | + | |<math>4.6 \pm 2.0</math><ref name="Gold_1970"></ref> |
|mM | |mM | ||
|- | |- | ||
Line 256: | Line 256: | ||
|- | |- | ||
|<math>K_{Glyf}</math> | |<math>K_{Glyf}</math> | ||
− | |1.7 <ref name=" | + | |<math>1.7 \pm 0.4</math><ref name="Gold_1970"></ref> |
|mM | |mM | ||
|- | |- |
Revision as of 16:09, 8 May 2014
Glycogen phosphorylase (GP) is a dimeric enzyme that catalyses the reaction in which the terminal glucose residue from a glycogen chain is phosphorylated and cleaved from the chain, releasing it as Glc1P.
Contents
Chemical equation
![Glycogen_{n+1} + Pi \rightleftharpoons Glycogen_{n} + Glc1P](/wiki/images/math/8/6/4/86402737c580a1f36c691d2a13dcbb43.png)
Rate equation
MWC model was used to formualte the rate law. [1]
![\frac{V_{max} \times n \times \frac{[Pi]}{K_{r,Pi}} \left( 1 + \frac{[Pi]}{K_{r,Pi}} + \frac{[Glc1P]}{K_{r,Glc1P}} \right)^{n-1} }{\left( 1 + \frac{[Pi]}{K_{r,Pi}} + \frac{[Glc1P]}{K_{r,Glc1P}} \right)^n + L_u \left( 1 + \frac{[Pi]}{K_{u,Pi}} + \frac{[Glc1P]}{K_{u,Glc1P}} \right)^n \left( \frac{1 + \frac{[Glc6P]}{K_{u,Glc6P}}}{1 + \frac{[AMP]}{K_{r,AMP}} + \frac{[Glc6P]}{K_{r,Glc6P}}} \right)^n } + \frac{V_{max} \times n \times \frac{[Pi]}{K_{r,Pi}} \left( 1 + \frac{[Pi]}{K_{r,Pi}} + \frac{[Glc1P]}{K_{r,Glc1P}} \right)^{n-1} }{\left( 1 + \frac{[Pi]}{K_{r,Pi}} + \frac{[Glc1P]}{K_{r,Glc1P}} \right)^n + L_t \left( 1 + \frac{[Pi]}{K_{t,Pi}} + \frac{[Glc1P]}{K_{t,Glc1P}} \right)^n \left( \frac{1 + \frac{[AMP]}{K_{t,AMP}} \frac{[Glc6P]}{K_{t,Glc6P}}}{1 + \frac{[AMP]}{K_{r,AMP}} + \frac{[Glc6P]}{K_{r,Glc6P}}} \right)^n \left( 1 + \frac{[ATP]}{K_{t,ATP}} \right)^n }](/wiki/images/math/7/e/5/7e599d4304d1f49ee3e3d2d32f556863.png)
An alternative rate equation without considering the allosteric regulation is given as [2]
![\frac{V_{maxf} \frac{Glycogen_{n+1} \times Pi}{K_{iGlyf} \times K_{Pi}} -\frac{V_{maxf} \times K_{Glyb} \times K_{iGlc1P}}{K_{iGlyf} \times K_{Pi} \times Keq} \times \frac{Glycogen_n \times Glc1P}{K_{Glyb} \times K_{iGlc1P}} }{1 + \frac{Glycogen_{n+1}}{K_{iGlyf}} + \frac{Pi}{K_{iPi}} + \frac{Glycogen_n}{K_{iGlyb}} + \frac{Glc1P}{K_{iGlc1P}} \frac{Glycogen_{n+1} \times Pi}{K_{Glyf} \times K_{iPi}} + \frac{Glycogen_n \times Glc1P}{K_{Glyb} \times K_{iGlc1P}} }](/wiki/images/math/4/f/d/4fde226c3e0ac69f2acec27accdd7d71.png)
Parameter values
Parameter | Value | Units | Organism | Remarks |
---|---|---|---|---|
![]() |
2 | Dimensionless | Recombinant, human muscle | |
![]() |
50 | ![]() | ||
![]() |
2.08 | mM | ||
![]() |
4.32 | mM | ||
![]() |
41.53 | mM | ||
![]() |
0.67 | mM | ||
![]() |
82.02 | mM | ||
![]() |
27.92 | mM | ||
![]() |
![]() |
mM | ||
![]() |
0.53 | mM | ||
![]() |
3.9 | mM | ||
![]() |
7.42 | mM | ||
![]() |
0.56 | mM | ||
![]() |
0.27 | mM | ||
![]() |
5.93 | Dimensionless | ||
![]() |
34741 | Dimensionless |
The parameter for the alternative equation are
Parameter | Value | Units | Organism | Remarks |
---|---|---|---|---|
![]() |
50 [1] | ![]() |
Rabbit | |
![]() |
15[2] | mM | ||
![]() |
4 [2] | mM | ||
![]() |
0.15 [2] | mM | ||
![]() |
10.1 [2] | mM | ||
![]() |
4.6 [2] | mM | ||
![]() |
4.4 [2] | mM | ||
![]() |
1.7 [2] | mM | ||
![]() |
0.42 [2] | mM |
Parameters with uncertainty
Parameter | Value | Units | Organism | Remarks |
---|---|---|---|---|
![]() |
2 | Dimensionless | Recombinant, human muscle | |
![]() |
![]() |
![]() | ||
![]() |
![]() |
mM | ||
![]() |
![]() |
mM | ||
![]() |
![]() |
mM | ||
![]() |
![]() |
mM | ||
![]() |
![]() |
mM | ||
![]() |
![]() |
mM | ||
![]() |
![]() |
mM | ||
![]() |
![]() |
mM | ||
![]() |
![]() |
mM | ||
![]() |
![]() |
mM | ||
![]() |
![]() |
mM | ||
![]() |
![]() |
mM | ||
![]() |
![]() |
Dimensionless | ||
![]() |
![]() |
Dimensionless |
The parameter for the alternative equation are
Parameter | Value | Units | Organism | Remarks |
---|---|---|---|---|
![]() |
50 [1] | ![]() |
Rabbit | |
![]() |
15[2] | mM | ||
![]() |
![]() |
mM | ||
![]() |
![]() |
mM | ||
![]() |
![]() |
mM | ||
![]() |
![]() |
mM | ||
![]() |
4.4 [2] | mM | ||
![]() |
![]() |
mM | ||
![]() |
0.42 [2] | mM |
References
- ↑ 1.0 1.1 1.2 Palm, D.C. (2013). The regulatory design of glycogen metabolism in mammalian skeletal muscle (Ph.D.). University of Stellenbosch
- ↑ 2.00 2.01 2.02 2.03 2.04 2.05 2.06 2.07 2.08 2.09 2.10 2.11 Lambeth M.J. & Kushmerick M.J. (2002). A computational model for glycogenolysis in skeletal muscle. Ann Biomed Eng 30, 808–827
- ↑ 3.0 3.1 3.2 3.3 3.4 Gold, A. M., R. M. Johnson, and J. K. Tseng (1970), Kinetic mechanism of rabbit muscle glycogen phosphorylase a,J. Biol. Chem. 245:2564 –2572, 1970