SDS gel electrophoresis is used extensively to separate and identify denatured proteins. However, because this method relies on protein size alone, little information about proteins with the same molecular weight can be obtained. Peptide mapping is one of a number of techniques used to study the relatedness of similarly sized proteins. With this method, proteases are used to cut proteins into smaller peptide fragments and the fragments derived from two or more proteins are compared. The number and size of fragments generated from a protein are determined largely by the protein’s amino acid sequence, since proteases break peptide bonds adjacent to preferred amino acid residues. In this exercise, students use peptide mapping to compare the structural relatedness of serum albumin from the human, cow, chicken and pigeon. Typical results of the exercise are shown.
Each of the individual experiments are supplied with the chemicals and laboratory guides needed for 16 students working in pairs. If you chose one or more of the experiments from this series – you should also order Electrophoresis Package 2M or Electrophoresis Package 2. Electrophoresis Package 2M provides sufficient agarose, gel stain, and electrophoresis buffers for 1 of the individual experiments in this series (four gels with 15ml of agarose per gel). Electrophoresis Package 2 provides sufficient agarose, gel stain, and electrophoresis buffers for up to 6 of the individual experiments in this series.
If ordering the EXP-204P variant, precast polyacrylamide gels are not included. Precast polyacrylamide gels can be ordered from Bio Rad, (800-424-6723) Their catalog number is 4561093EDU.