Automated Subpicomole Protein Sequencing Using an Alternative Postcleavage Conversion Chemistry

Abstract

An automated subpicomole sequencing method is described. It is based on a chemistry that generates easily detectable amino acid derivatives from the postcleavage products of the classical Edman degradation. These products, which include the amino acid anilinothiazolinone (ATZ), phenyithiocarbamyl (PTC), and phenyithiohydantoin (PTH), are converted to a homogeneous preparation of ATZ that can react with sensitivity-enhancing compounds such as fluorescent amines. The method is demonstrated with a protein of known sequence (α-lactalbumin) and appears to offer a significant improvement over current high-sensitivity protein sequencing strategies. Modifications to the sequencer hardware or to the Edman degradation chemistry are not required.