sds page (gel preparation) - (Feb/11/2008 )
I have a question about preparing my gels.
I do not know what is the difference between 40% acrylamide/bisacrylamide (29:1 ratio) and 40% acrylamide/bisacrylamide (19:1 ratio)- is it important? How do I make the calculations for a gel of 10% and 12,5%. Please help!
Annabella
I do not know what is the difference between 40% acrylamide/bisacrylamide (29:1 ratio) and 40% acrylamide/bisacrylamide (19:1 ratio)- is it important? How do I make the calculations for a gel of 10% and 12,5%. Please help!
Annabella
the percentage is the concentration of total acrylamide including bisacrylamide; the ratio is acrylamide to bisacrlymade:
40% (29:1) = 36,67% AA+ 1,33% bis-AA;
higher share of bis-AA increases cross-linking
"higher share of bis-AA increases cross-linking"
Thank you.
I have one more question: is the cross-linking only faster, or are the pores smaller where the precentage of bis-AA is higher?
Thank you so much!
Anabella
the pores are smaller when bis is higher (more crosslinking). they are also smaller when higher total acrylamide concentration.
in general, 29:1 and 37.5:1 is used for protein gels, 19:1 is used for nucleic acid gels (not a hard and fast rule).
Thank you so much!
Anabella