DNA Stabilization Buffer

DNA Stabilization Buffer (250 ml)        
Component    Volume (ml)    [Final]
1 M NaCl    1.461 g    0.1 M
Tris HCl    2.5    0.01 M
0.5M EDTA    5    0.01 M
10% SDS    12.5    0.014 M
Proteinase K Solution (20 mg/ml)    2.5    6.92x10-6 M
ddH2O    227.5    
Proteinase K Solution (20 mg/ml)        
Component    Volume (ml)    [Final]
Proteinase K powder    500 mg    6.92x10-4 M
ddH2O    25    

Prepared saliva samples were centrifuged at 12,851 g for 10  min  and  pellets  were  resuspended  in  200 μL  of  SE  buffer  (75 mM NaCl; 25 mM EDTA, pH 8.0). 35  μL  of 20  mg/mL  proteinase  K  and  10 μL  of  10% SDS  were  added.  The  samples were digested at 55 °C for 3 h and DNA was extracted with equal  volumes  of  phenol-chloroform  (1:1).  DNA  was  precipitated  from  the  supernatant  with  3  M  sodium  acetate  (pH  6.0;  volume  40  μL) and two volumes of cold 100 %  ethanol and a following incubation at  –20°C for 15 – 30 min. The DNA was pelleted at 20,817 gfor 25 min, and dried at 37 ° C. The pellet was resuspended in 30 μL redistilled water at 55 ° C for 30 min.