| | Molecule Name/
Site Name | Km (uM) | kcat (1/s) | Ratio
(k2/k3) | Enzyme Type | Substrate | Product |
| 1 |
Enzyme Activity:
CaM.PDE1
Enzyme Molecule:
CaM.PDE1 | 39.6831 | 10 | 4 | explicit E-S complex | cAMP
| AMP
|
| | Max activity ~10umol/min/mg in presence of lots of CaM. Affinity is low, 40 uM. k3 = 10, k2 = 40, k1 = (50/40) / 6e5. |
| 2 |
Enzyme Activity:
kenz
Enzyme Molecule:
AC1-CaM | 299.998 | 4.5 | 4 | Classical Michaelis-Menten
V = Etot.S.Kcat/Km+S | ATP
| cAMP
|
| | 17 Feb 2005 Halved Vmax as the amount of enzyme has been doubled to get an integer value in the spine. 18 Feb 2005. Updated Km from BRENDA: EC No 4.6.1.1 Rat Km: 0.95 mM Turnover 12/sec. Human Km: 0.3 mM 12 umol/min/mg for mammalia, turnover is 12/sec See PMID 8663304 by Dessauer and Gilman JBC 271 1996 Unfortunately turnover range is from 34 down to 0.1 in different studies, according to BRENDA. |
| 3 |
Enzyme Activity:
kenz
Enzyme Molecule:
AC2* | 300.002 | 2 | 4 | Classical Michaelis-Menten
V = Etot.S.Kcat/Km+S | ATP
| cAMP
|
| | Reduced Km to match expt data for basal activation of AC2 by PKC. Now k1 = 2.9e-6, k2 = 72, k3 = 18 18 Feb: Raised Km to 300 based on BRENDA data. Unlikely to make much difference, given the vast amount of ATP. |
| 4 |
Enzyme Activity:
PDE
Enzyme Molecule:
cAMP-PDE | 19.8411 | 10 | 4 | explicit E-S complex | cAMP
| AMP
|
| | Best rates are from Conti et al Biochem 34 7979-7987 1995. Though these are for the Sertoli cell form, it looks like they carry nicely into alternatively spliced brain form. See Sette et al JBC 269:28 18271-18274 Km ~2 uM, Vmax est ~ 10 umol/min/mg for pure form. Brain protein is 93 kD but this was 67. So k3 ~10, k2 ~40, k1 ~4.2e-6 |
| 5 |
Enzyme Activity:
PDE*
Enzyme Molecule:
cAMP-PDE* | 19.8413 | 20 | 4 | explicit E-S complex | cAMP
| AMP
|
| | This form has about twice the activity of the unphosphorylated form. See Sette et al JBC 269:28 18271-18274 1994. We'll ignore cGMP effects for now. |
| 6 |
Enzyme Activity:
PDE1
Enzyme Molecule:
PDE1 | 39.6999 | 1.667 | 4.0012 | explicit E-S complex | cAMP
| AMP
|
| | Rate is 1/6 of the CaM stim form. We'll just reduce all lf k1, k2, k3 so that the Vmax goes down 1/6. |
