In article <1994May25.091849.28879 at waikato.ac.nz>, pjc at waikato.ac.nz (Peter Charlton) writes:
>Sorry to trouble the net with such a trivial question, but for some reason I
>can't find a single consistent answer.
>What is the minimum amount of protein needed to obtain an N-terminal sequence
>of 5-6 residues?
>>Many thanks,
>Peter.
The first question from me is "How much sample are you willing to sacrifice?"
Basic rule of thumb is that 50% of the sample load is consumed by the Edman
Degradation chemistry for the first cycle. Also, the amount of 'background'
noise from the PTH column determines in my lab how sensitive I can call down in
picomole amounts. With the equipment running here, I feel that I can
consistently call down to 1 picomole, even less if the background is behaving.
So my answer to your question would be "10 picomoles" especially if it is
protein. Short peptides are another story.
This is my opinion. I am sure that others in the field will differ, especially
the super-sensitive core facilities. Tom
