title: Evolution of amino acid biosynthesis and enzymes with broad substrate specificity.
abstract: I selected 82 proteins that were related to amino acid biosynthesis in the genome of Escherichia coli. I then searched the extensive sequence homology for each of the selected proteins from among the proteins of E.coli. The result showed that 30 proteins of the selected proteins had extensive sequence homology within the selected proteins, and 21 proteins had extensive sequence homology to proteins outside the selected proteins. In addition, the enzymes with broad substrate specificity play an important role in the amino acid biosynthesis. I demonstrate here that some substrate-specific enzymes evolved from an ancestor enzyme with broad substrate specificity.
  
  
  BACKGROUND
  hnishida@iam.u-tokyo.ac.jp
authors.affiliation: Institute of Molecular and Cellular Biosciences, The University of Tokyo, Tokyo 113-0032, Japan. hnishida@iam.u-tokyo.ac.jp
authors.forename: H
authors.initials: H
authors.lastname: Nishida
mesh_terms: D000596:Amino Acids / Q000096:biosynthesis*; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000145:classification / Q000235:genetics*; D004798:Enzymes / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics*; D019143:Evolution, Molecular; D010802:Phylogeny; D013379:Substrate Specificity
chemical_list: D000596:Amino Acids; D001426:Bacterial Proteins; D004798:Enzymes