Today I have prepared 4 samples, a new lysis buffer with 1% SDS and new proteinase K aliquouts. This time I chopped feather tips to pieces with sterile razor blades. I preaperd 2 samples each with the original and 1% SDS buffers. And used 5 µg/ml of proteinase K for one of the tubes and 20 µg/ml for the other. So it is:
Lysis Buffer 1 (2% SDS): First tube 5 µg/ml ProK, Second tube 20 µg/ml ProK
Lysis Buffer 2 (1% SDS): First tube 5 µg/ml ProK, Second tube 20 µg/ml ProK
All the samples have been incubating in dry block thermostat at 56C degrees for 4 hours. The samples are as if I just put them there. There is no change. Somehow it feels like proteinase K is not activated at all. I don't know what to do. I'll leave them incubating till tomorrow but I don't expect any changes.