Identification of proteins in sequence databases from amino acid composition data

Having obtained the amino acid composition of a protein, chemists and molecular biologists may wish to identify the protein from this data alone. In general such data will have errors associated with them and the length of the protein may be known only approximately or not at all. In this paper a method is described which enables searching of protein sequence databases for sequences or fragments of sequences which have a composition similar to the one being sought. Such searches are generally quite discriminating as shown by the examples provided. This method has been implemented as part of the computer program Scrutineer and is being freely distributed. It is simple to use.