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Molecule Parameter List for ATP

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

*ATP* participated as	Molecule	Sum total of	Enzyme	Substrate of an enzyme	Product of an enzyme	Substrate in Reaction	Product in Reaction
No. of occurrences	1	0	0	5	0	0	0

Accession and Pathway Details

Accession Name	Accession No.	Accession Type	Pathway Link
Synaptic_ Network	16	Network	Shared_Object_Synaptic_Network, PKC, PLA2, PLCbeta, Gq, MAPK, Ras, EGFR, Sos, PLC_g, CaMKII, CaM, PP1, PP2B, PKA, AC, CaRegulation
This model is an annotated version of the synaptic signaling network. The primary reference is Bhalla US and Iyengar R. Science (1999) 283(5400):381-7 but several of the model pathways have been updated. Bhalla US Biophys J. 2002 Aug;83(2):740-52 Bhalla US J Comput Neurosci. 2002 Jul-Aug;13(1):49-62

ATP acting as a Molecule in Synaptic_Network Network

Name	Accession Name	Pathway Name	Initial Conc. (uM)	Volume (fL)	Buffered
ATP	Synaptic_ Network Accession No. : 16	AC Pathway No. : 85	5000	1000	Yes
ATP is present in all cells between 2 and 10 mM. See Lehninger.

ATP acting as a Substrate for an Enzyme in Synaptic_Network Network

	Enzyme Molecule / Enzyme Activity	Accession Name	Pathway Name	Km (uM)	kcat (s^-1)	Ratio	Enzyme Type	Reagents
1	AC1-CaM / kenz	Synaptic_ Network Accession No. : 16	AC Pathway No. : 85	20	18	4	Classical Michaelis-Menten V = Etot.S.Kcat/Km+S	Substrate ATP Product cAMP
	Vmax is assumed to be the same as that for the Gs-stimulated form. The rates are from: Smigel 1986 JBC 261(4):1976-1982 who has 8.27 umol/min/mg with forskolin stimulated AC. Tang et al JBC 266(13):8595-8603 have an almost identical Vmax of 8 umol/min/mg. This comes to a Vmax of 18/sec. The Km is pretty immaterial since the vast excess of ATP means that the enzyme will normally be saturated. This is a pretty fast enzyme. Note that the saturation of the enzyme means that the regulatory reactions have to involve the complex rather than the free enzyme.
2	AC2* / kenz	Synaptic_ Network Accession No. : 16	AC Pathway No. : 85	20.1149	7	4	Classical Michaelis-Menten V = Etot.S.Kcat/Km+S	Substrate ATP Product cAMP
	The Vmax is scaled down to 7/sec from the Gs-stimulated form. This is constrained because we have a measure of basal activity due to basal phosphorylation by PKC. Two papers measure activation of AC2 by phosphorylation without Gs: Jacobowitz et al JBC 268(6):3829-3832 (Stim 3x) and Yoshimura and Cooper 1993 JBC 26(7):4604-4607 (Stim 9x). The conditions are somewhat different in the two cases. The reference maximally stimulated Vmax is 18/sec from Smigel 1986 JBC 261(4):1976-1982 who has 8.27 umol/min/mg with forskolin stimulated AC. Tang et al JBC 266(13):8595-8603 have an almost identical Vmax of 8 umol/min/mg. This comes to a Vmax of 18/sec. The Km is pretty immaterial since the vast excess of ATP means that the enzyme will normally be saturated. This is a pretty fast enzyme. Note that the saturation of the enzyme means that the regulatory reactions have to involve the complex rather than the free enzyme.
3	AC2-Gs / kenz	Synaptic_ Network Accession No. : 16	AC Pathway No. : 85	20	18	4	Classical Michaelis-Menten V = Etot.S.Kcat/Km+S	Substrate ATP Product cAMP
	Vmax is assumed to be the same as for AC1. This is consistent since there is a good match between the mixture of ACs tested by Smigel 1986 JBC 261(4):1976-1982 who has 8.27 umol/min/mg with forskolin stimulated AC. Tang et al JBC 266(13):8595-8603 have an almost identical Vmax of 8 umol/min/mg for AC1. This comes to a Vmax of 18/sec. The Km is pretty immaterial since the vast excess of ATP means that the enzyme will normally be saturated. This is a pretty fast enzyme. Note that the saturation of the enzyme means that the regulatory reactions have to involve the complex rather than the free enzyme.
4	AC1-Gs / kenz	Synaptic_ Network Accession No. : 16	AC Pathway No. : 85	20	18	4	Classical Michaelis-Menten V = Etot.S.Kcat/Km+S	Substrate ATP Product cAMP
	Vmax is from Smigel 1986 JBC 261(4):1976-1982 who has 8.27 umol/min/mg with forskolin stimulated AC. Tang et al JBC 266(13):8595-8603 have an almost identical Vmax of 8 umol/min/mg. This comes to a Vmax of 18/sec. The Km is pretty immaterial since the vast excess of ATP means that the enzyme will normally be saturated. This is a pretty fast enzyme. Note that the saturation of the enzyme means that the regulatory reactions have to involve the complex rather than the free enzyme.
5	AC2*-Gs / kenz	Synaptic_ Network Accession No. : 16	AC Pathway No. : 85	60	54	4	Classical Michaelis-Menten V = Etot.S.Kcat/Km+S	Substrate ATP Product cAMP
	The Km is higher here but it is still well below the level of ATP so the enzyme remains saturated. The Vmax is 3x higher than the reference forskolin stimulated form. This scale factor is a compromise between the 2x rise reported by Jacobowitz et al JBC 268(6): 3829-3832 and the 9x rise reported by Yoshimura and Cooper 1993 JBC 268(7):4604-4607. The reference Vmax is from Smigel 1986 JBC 261(4):1976-1982 who has 8.27 umol/min/mg with forskolin stimulated AC. Tang et al JBC 266(13):8595-8603 have an almost identical Vmax of 8 umol/min/mg. This comes to a Vmax of 18/sec. The Km is pretty immaterial since the vast excess of ATP means that the enzyme will normally be saturated. This is a pretty fast enzyme. Note that the saturation of the enzyme means that the regulatory reactions have to involve the complex rather than the free enzyme.

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