वृद्धि दर स्थिरांक कैलकुलेटर — सूत्र
## PCR Primer Melting Temperature
Accurate Tm prediction is essential for PCR primer design. The salt-corrected formula accounts for ionic strength effects on DNA stability.
### Salt-Corrected Formula
**Tm = 81.5 + 16.6 × log10([Na+]) + 41 × (GC fraction) - 675/N**
where [Na+] is in moles/L and N is the primer length. The annealing temperature for PCR is typically set 3-5°C below the primer Tm.
Accurate Tm prediction is essential for PCR primer design. The salt-corrected formula accounts for ionic strength effects on DNA stability.
### Salt-Corrected Formula
**Tm = 81.5 + 16.6 × log10([Na+]) + 41 × (GC fraction) - 675/N**
where [Na+] is in moles/L and N is the primer length. The annealing temperature for PCR is typically set 3-5°C below the primer Tm.
हल किया गया उदाहरण
A 22-mer primer with 12 GC bases at 50 mM Na+.
- GC fraction = 12/22 = 0.5455
- Tm = 81.5 + 16.6 × log10(0.050) + 41 × 0.5455 - 675/22
- Tm = 81.5 + 16.6 × (-1.301) + 22.36 - 30.68
- Tm = 81.5 - 21.60 + 22.36 - 30.68 = 51.58°C
- Annealing temp ≈ 51.58 - 5 = 46.58°C