MBIO 3460 Lecture Notes - Lecture 23: Osmotic Shock, Proteolysis, Epitope
9 Apr 2018
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Describe how proteins can be labeled using both immunological and chemical labeling techniques and include specific problems associated with each labeling technique. Best used on: purified proteins, proteoliposomes, proteins in the isolated natural membranes, whole cells or organelles. Knowledge of the protein sequence allows prediction of peptide formation from the purified protein. All peptides that result from the enzymatic digestion are isolated and compared by sds- Page: comparison of all of the digestion products from all protein/lipids complexes should indicate which peptides are located where, peptide maps are generated. Individual proteins can be sequenced: protein may be excised from the gel for sequencing. Disadvantage: exposed protein sites are not normally susceptible to proteolytic cleavage. The protein/membrane is exposed to a variety of enzymes such as: trypsin: cleaves at lys-arg, chymotrypsin: cleaves at non-polar amino acids (phe, trp, tyr, thermolysin: cleaves at leu, ileu, val, cyanogen: bromide cleaves at met.
