Mass distribution, polydispersity and focusing properties of carrier ampholytes for IEF. IV: pH 6-8 intervals.
Four commercial brands of carrier ampholytes (Ampholine, Pharmalyte, Servalyt, Bio-Lyte), in the pH 6-8 range, have been analyzed by a 2-D technique based on preparative Rotofor fractionation followed by CE-MS of 10 out of 20 fractions harvested, in the second dimension. The findings: Ampholine (pH 6-8) contains 80 different M(r) compounds, in the M(r) interval 216-979 Da, for a total of 326 isoforms. Bio-Lyte (pH 6-8) consists of 62 different M(r) species, in the M(r) range 341-1048 Da, for a total of 237 isoforms. Servalyt (pH 6-8) is made of 126 different M(r) compounds, in the M(r) interval 240-785 Da, for a total of 703 isoforms. Pharmalyte (pH 5-8) comprises 123 amphoteres, in the M(r) range of 221-992 Da, for a total of 476 isoforms. Pharmalyte appears to be the best brand, with a good proportion of species focusing sharply at their pI position and relatively few 'poor' species, distributed along the entire pH gradient. General conclusions are drawn on the properties of all the pH intervals explored in this series of investigations and some guidelines for possible synthetic routes ameliorating the neutral and alkaline pH intervals are discussed.
Simó
Carolina
C
Politecnico di Milano, Department of Chemistry, Materials and Engineering Chemistry Giulio Natta, Milano, Italy.
Citterio
Attilio
A
Righetti
Pier Giorgio
PG
D000665:Ampholyte Mixtures / Q000032:analysis* / Q000737:chemistry*; D005591:Chemical Fractionation / Q000379:methods; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D019075:Electrophoresis, Capillary / Q000379:methods; D004591:Electrophoresis, Polyacrylamide Gel / Q000379:methods; D006863:Hydrogen-Ion Concentration; D007525:Isoelectric Focusing / Q000379:methods*; D007526:Isoelectric Point; D008970:Molecular Weight; D011108:Polymers / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods
D000665:Ampholyte Mixtures; D011108:Polymers