title: Amino acid compositions of proteins and their identities.
abstract: A critical overview is given on the application of amino acid composition data for the establishment of the protein's identity (amino acids composition vs. protein identity, the AAC-PI method). Several criteria are used to measure the differences between the amino acid compositions of various proteins. The AAC-PI method unambiguously identifies proteins which belong to the families with a high phylogenetic conservancy of their sequences. The identification of pure proteins can be accomplished with a relatively high level of confidence. The AAC-PI method, however, sometimes needs the support of N-terminal or internal sequencing of proteins since, alone, it cannot distinguish whether the lack of finding a candidate protein in protein data bases is because the investigated amino acid composition corresponds to an unknown protein or its processed form or because it is a sum of at least two protein components, or whether it is due to other experimental errors. The identification of a few new proteins such as "arginine-rich protein", macrophage migration inhibitory factor (MIF) and the preformed neurotrophic factor present in the calf brain cytosol is also reported.
mesh_terms: D000465:Algorithms; D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis*; D000818:Animals; D002417:Cattle; D016208:Databases, Factual; D006801:Humans; D008969:Molecular Sequence Data; D008970:Molecular Weight; D011506:Proteins / Q000737:chemistry* / Q000302:isolation & purification; D012995:Solubility; D014867:Water / Q000737:chemistry
chemical_list: D000596:Amino Acids; D011506:Proteins; D014867:Water