Quantitative analysis of the amino-terminal residues of spectrin by use of the transamination reaction.

The metal ion-catalysed transamination reaction has been examined as a means of quantitative amino-terminal analysis of proteins. Application of this method to the erythrocyte membrane protein, spectrin, showed that this protein contained a single amino-terminal residue per 240,000 daltons. This value supports the hypothesis that spectrin is comprised of two polypeptide chains of approx. 220,000 and 250,000 daltons, respectively.