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Molecule Parameter List for NO

The statistics table lists the distribution of a molecule acting either as a substrate, product, enzyme or as a molecule within the network.
The text color of a molecule is highlighted by color.
Statistics
NO participated asMoleculeSum total ofEnzymeSubstrate of an enzymeProduct of an enzymeSubstrate in ReactionProduct in Reaction
No. of occurrences1000030

Accession and Pathway Details
Accession NameAccession No.Accession TypePathway Link
cGMP_regulation34Network
Shared_Object_cGMP_regulation GC PDE 
Though Corbin JD. et al. Eur J Biochem. (2000) 267(9):2760-7 has been mentioned in the citation, this model has been made with inputs from different literature sources, each of which has been mentioned in the notes sections. This model features hydrolysis of cGMP by bovine PDE, phosphorylation of PDE by bovine lung PKG, and activation of bovine lung PKG by cGMP binding. These mechanisms are known to be involved in cGMP level regulation. Rates have been used from different sources and the model has been tested based on Corbin JD. et al., since their work involved measuring the PDE phosphorylation and PDE activity.
On replicating Figures 2, 3 and 4 from their paper, there is approx 30% difference in results but the qualitative shape of the curves is very similar. This might be due to the fact that the Vmax values were used from different literature sources. This might lead to the discrepancy in the numbers in this model. The values shown in this model are near estimated physiological levels.In order to replicate the Figures more closely, we have run additional simulations with concentration terms changed so as to replicate the experimental conditions exactly.

NO acting as a Molecule in  
cGMP_regulation Network
NameAccession NamePathway NameInitial Conc.
(uM)
Volume
(fL)
Buffered
NOcGMP_regulation
Accession No. : 34
GC
Pathway No. : 177
0.10.0016667No
Endogenously produced NO concentrations in the course of signal transduction processes are < 100 nM. (Varner et al., Nitric oxide in the nervous system, Academic press, London, UK, pp.191-206.)

NO acting as a Substrate in a reaction in  
cGMP_regulation Network
Kd is calculated only for second order reactions, like nA+nB <->nC or nA<->nC+nD, where n is number and A,B,C,D are molecules, where as for first order reactions Keq is calculated. Kd for higher order reaction are not consider.
 NameAccession NamePathway NameKfKbKdtauReagents
1NO_bind_sGCfastcGMP_regulation
Accession No. : 34
GC
Pathway No. : 177
700
(uM^-1 s^-1)
800
(s^-1)
Kd(bf) = 1.1429(uM)-Substrate
NO
sGCfast

Product
NO.sGCfast
  This is the fast binding of NO to sGC, subsequently activating it, as proposed by Stone and Marletta. Rates of these binding reactions used directly from Stone and Marletta,1996, Biochemistry, 35(4):1093-1099, based on whose paper this model is made. Rates obtained from stopped flow kinetics detailed in their paper.
2NObindnonhemecGMP_regulation
Accession No. : 34
GC
Pathway No. : 177
5
(uM^-1 s^-1)
25
(s^-1)
Kd(bf) = 5(uM)-Substrate
NO
NO.sGC6coord

Product
nonhemebind_int
  This step is the one that differs from the fast reaction scheme, as reported by Stone and Marletta. Here the reaction is dependent upon the binding of NO to an unidentified non-heme site on the protein. Rates used directly from Stone and Marletta,1996, Biochemistry, 35(4):1093-1099.
3NO_bind_sGCslowcGMP_regulation
Accession No. : 34
GC
Pathway No. : 177
700
(uM^-1 s^-1)
800
(s^-1)
Kd(bf) = 1.1429(uM)-Substrate
NO
sGCslow

Product
NO.sGCslow
  This is the slow binding of NO to sGC, as reported by Stone and Marletta,1996, Biochemistry, 35(4):1093-1099. The rates shown have been used directly from their data from stopped flow kinetics.



Database compilation and code copyright (C) 2022, Upinder S. Bhalla and NCBS/TIFR
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