[52] Sequential degradation plus dansylation

TLDR: This chapter describes the procedure and applicability of the sequential degradation plus dansylation method, used extensively in several investigations of the amino acid sequences of proteins, notably that of α-chymotrypsin.

Abstract: Publisher Summary This chapter describes the procedure and applicability of the sequential degradation plus dansylation method. This procedure is used extensively in several investigations of the amino acid sequences of proteins, notably that of α-chymotrypsin. All normal protein amino acids are encountered, and with few exceptions provided no difficulties. The yields of dansyl end groups decline slowly during successive stages of the degradation, and it is necessary to progressively increase the size of sample used for reaction. The method employs direct identification of the end groups with the very sensitive dansyl chloride technique. Approximately 1-5 millimicromoles are required for each step of the degradation, so that 20 millimicromoles is usually sufficient to establish the complete sequence of a penta- or hexapeptide. The limiting factor is the capacity of the electrophoresis equipment used in identifying end groups.