For the 492 sequencer, which is what we currently use, there is a minimum amount for sequence analysis of about 1 picomole. There is also a limit on the maximum amount of PVDF membrane which the instrument can accommodate. Generally, no more PVDF than would be obtained from the transfer of a 1 cm wide by 1-2 mm high gel band will fit and still work properly. If in doubt, it is a good policy to check with us before preparing your sample. The probability that no sequence, limited sequence, or poor sequence will be obtained increases with decreasing sample amount.
Current sensitivity is limited both by sample purity and hardware.
Accuracy is limited by the expertise of the laboratory personnel. We once successfully obtained sequence with 0.3 picomoles loaded, and we have also failed at levels higher than this. Remember that for a 1 picomole load, the anticipated yield is 550 femtomoles and signal declines exponentially with the number of cycles. By molecular weight is meant subunit molecular weight. This can be estimated from SDS gel electrophoresis.