Abstract: A modified Edman degradation process is used to obtain compositional tags for proteins. The Edman degradation chemistry is separated from amino acid analysis, circumventing the serial requirement of the conventional Edman process. Multiple cycles of coupling and cleavage are performed prior to extraction and compositional analysis of amino acids. The amino acid composition information is used to search a database of known protein or DNA sequences to identify the sample protein.

Abstract: A method is provided for sequencing peptides and proteins in which the coupling and cleavage reagents are supplied through a valve block assembly with internal delivery channels and a common outlet channel. The outlet channel communicates with a reaction chamber in which the sample is placed. Access of reactants to the delivery channels is controlled by diaphragm valves, preferably equipped with relief grooves to accommodate deformation of the diaphragm. Reservoirs feeding the delivery channels have an inert atmosphere controlled by pressurizing and venting channels in the valve block. Exposure of plastic tubing to oxygen is kept to a minimum. Reactants are thereby supplied without significant cross-contamination or oxidative decomposition.

Abstract: A valve block assembly with internal delivery channels and a common outlet channel is provided. Access of reactants to the delivery channels is controlled by diaphragm valves, preferably equipped with relief grooves to accommodate deformation of the diaphragm. Reservoirs feeding the delivery channels have an inert atmosphere controlled by pressurizing and venting channels in the valve block. Exposure of plastic tubing to oxygen is kept to a minimum. The assembly is particularly adapted for use in a DNA or protein sequencer to supply reactants without cross-contamination or oxidative decomposition.

Abstract: A valve block assembly with internal delivery channels and a common outlet channel is provided. The assembly has two delivery valve surfaces with access to the common channel. The common channel comprises easily cleaned linear sections running alternately from one surface to the other, and connecting surface grooves at the valve sites. Diaphragm valves with relief grooves to accommodate deformation of the diaphragm are provided. The V-like cross-section of the connecting grooves of the common channel and the conical shape of the nearby outlet of a delivery channel assure that the valve may be opened by only a small actuating force. Reservoirs feeding the delivery channels have an inert atmosphere controlled by pressurizing and venting channels in the valve block. Exposure of plastic tubing to oxygen is kept to a minimum. The assembly is particularly adapted for use in a protein sequencer to supply reactants without cross-contamination or oxidative decomposition.