Editing Gel electrophoresis (section)

===Polyacrylamide===
{{main|Polyacrylamide gel electrophoresis}}

Polyacrylamide gel electrophoresis (PAGE) is used for separating proteins ranging in size from 5 to 2,000 kDa due to the uniform pore size provided by the polyacrylamide gel. Pore size is controlled by modulating the concentrations of acrylamide and bis-acrylamide powder and by the [[QPNC-PAGE#Gel properties and polymerization time|polymerization time]] used in creating a gel. Care must be used when creating this type of gel, as acrylamide is a potent neurotoxin in its liquid and powdered forms.

Traditional [[DNA sequencing]] techniques such as [[Maxam–Gilbert sequencing|Maxam-Gilbert]] or [[Dideoxy termination#Chain termination method|Sanger]] methods used polyacrylamide gels to separate DNA fragments differing by a single base-pair in length so the sequence could be read. Most modern DNA separation methods now use agarose gels, except for particularly small DNA fragments. It is currently most often used in the field of [[immunology]] and protein analysis, often used to separate different proteins or [[isoforms]] of the same protein into separate bands. These can be transferred onto a [[nitrocellulose]] or [[PVDF]] membrane to be probed with antibodies and corresponding markers, such as in a [[western blot]].

Typically [[resolving gels]] are made in 6%, 8%, 10%, 12% or 15%.  Stacking gel (5%) is poured on top of the resolving gel and a gel comb (which forms the wells and defines the lanes where proteins, sample buffer, and ladders will be placed) is inserted.  The percentage chosen depends on the size of the protein that one wishes to identify or probe in the sample. The smaller the known weight, the higher the percentage that should be used. Changes in the buffer system of the gel can help to further resolve proteins of very small sizes.<ref name="pmid17406207">{{cite journal | author=Schägger H | title=Tricine-SDS-PAGE. | journal=Nat Protoc | year=2006 | volume=1 | issue=1 | pages=16–22 | pmid=17406207 | doi=10.1038/nprot.2006.4 | pmc= | s2cid=209529082 | url=https://pubmed.ncbi.nlm.nih.gov/17406207 | access-date=23 March 2022 | archive-date=11 June 2022 | archive-url=https://web.archive.org/web/20220611043435/https://www.nature.com/articles/nprot.2006.4 | url-status=live }}</ref>