BL/CH 401 Lecture #5 - Protein Primary Structure

Determination of Amino and Carboxyl Terminal Amino Acids of Proteins and Peptides

Determine N- and C- terminal amino acids,

so that you can easily recognize the N- and C- terminal peptides...

after the protein is cleaved into fragments.

N-terminal Determination: best method is the dansyl chloride:

{*Figure 9*}

General scheme for N-terminal amino acid determination.

Dansyl Chloride yields a fluorescent derivative of N-terminal amino acid...

so method is very sensitive!

Chemical structures for Dansyl chloride method:

{*Figure 10*} Dansyl method for N-terminal AA Determination.

C-terminal Determination: best method is enzymatic degradation with carboxypeptidase:

{*Figure 11*}

General scheme for C-terminal amino acid determination.

Usually several AAs are released from the C-terminal by carboxypeptidase,

so a time-course determination is done to see which AA is released first:

{*Figure 12*}

Carboxypeptidase treatment of a peptide: Xxx-----GluSerAla

©Wilbur H. Campbell, 1995, 1996; wcampbel@mtu.edu

Back To: Lecture 5 - Protein Primary Structure