10/3/2011
amino acid sequence
determination:
-isolate and determine its amino acid composition
Amino terminal amino acid determination - (label the amino terminal)
reagents commonly used: both react with free NH2 groups
1. Sanger reagent - 2, 4- fluorodinitrobenzene (FDNB). After reaction, hydrolyze the
peptide and will obtain the DNP alpha-amino acid as well as DNP-lysine where the DNP
is on the epsilon amino group.
-Has micromolar sensitivity 10^-6.
2. Dansyl chloride
- to react with free amino group and make Dansyl amino acid which is fluorescent. This
reagent will also react with the alpha amino group as well as the epsilon amino group of
lysine.
Nanomolar sensitivity - 10^-9
Carboxyl terminal amino acid determination- usually conducted using an enzyme that
can specifically remove the COOH terminal amino acid.
1. Carboxylpeptidase A- exopeptidase that can remove all the amino acids except lysine,
arginine or proline and will not remove any amino acid acid if proline is the penultimate
(next to the last or second form the right)
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- Fall '08
- Hilt
- amino acid sequence, terminal amino acid
-
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