| | Molecule Name/
Site Name | Km (uM) | kcat (1/s) | Ratio
(k2/k3) | Enzyme Type | Substrate | Product |
| 1 |
Enzyme Activity:
cyclase
Enzyme Molecule:
Gs.AC | 20 | 18 | 4 | Classical Michaelis-Menten
V = Etot.S.Kcat/Km+S | ATP
| cAMP
|
| | See Feinstein et al PNAS 88:10173-10177, Jacobowitz et al JBC 286(6):3829-3832 Smigel, JBC 261(4):1976-1982 (1986) |
| 2 |
Enzyme Activity:
PDE
Enzyme Molecule:
cAMP-PDE | 19.8413 | 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 |
| 3 |
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. |
