Peptide mass determination. You have isolated a protein from the bacterium E. coli and seek to confirm its identity by trypsin digestion and mass spectrometry. Determination of the masses of several peptide fragments has enabled you to deduce the identity of the protein. However, there is a discrepancy with one of the peptide fragments, which you believe should have the sequence MLNSFK and an (M 1 H)1 value of 739.38. In your experiments, you repeat edly obtain an (M 1 H)1 value of 767.38. What is the cause of this discrepancy and what does it tell you about the region of the protein from which this peptide is derived?

Peptide mass determination. You have isolated a protein from the bacterium E. coli and seek to confirm its identity by trypsin digestion and mass spectrometry. Determination of the masses of several peptide fragments has enabled you to deduce the identity of the protein. However, there is a discrepancy with one of the peptide fragments, which you believe should have the sequence MLNSFK and an (M 1 H)1 value of 739.38. In your experiments, you repeat edly obtain an (M 1 H)1 value of 767.38. What is the cause of this discrepancy and what does it tell you about the region of the protein from which this peptide is derived?

Biochemistry

6th Edition

ISBN:9781305577206

Author:Reginald H. Garrett, Charles M. Grisham

Publisher:Reginald H. Garrett, Charles M. Grisham

Chapter31: Completing The Protein Life Cycle: Folding, Processing, And Degradation

Section: Chapter Questions

Problem 17P

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