Glycine in gel; fiber typing - (Sep/09/2005 )

I'm attempting striated muscle fiber typing by electrophoresis and in gel staining (methods of Talmadge and Roy, 1993). Been having trouble with it but just realized that the published protocol is to have 0.1M glycine in the resolving gel. Proteins (myosin) are ~200kDa and the protocol is a long run (~24 hours) at ~70V to separate the isoforms of the protein. So, why glycine in the gel?...I've never seen this before. Anyone ever do fiber typing this way?

actually glycine acts as trailing ion.when the stacked proteins enter higher percentage resolving gel,its mobility is reduced so that its slower than glycine ions.in the resolving gel ,glycine's net negative charge will increase its mobility.thus the glycine overtakes some of the proteins and migrates directly behind the chloride ion,causing these proteins to resolve.