title: An active site-tyrosine-containing heptapeptide from D-amino acid oxidase.
abstract: The flavoenzyme D-amino acid oxidase (Eo) is rapidly chlorinated by N-chloro-D-leucine (Rudie, N.G., Porter, D.J.T., and Bright, H.J. (1980) J. Biol. Chem. 255, 498-508). We have carried out chymotryptic digestion of E0-36Cl2 and find that all of the radiolabel is located in a heptapeptide having [3.5-36Cl2]chlorotyrosine as the COOH-terminal residue. This heptapeptide, having the sequence -Asp-Leu-Glu-Arg-Gly-Ile-Tyr-, is located within a larger fragment obtained previously from cyanogen bromide cleavage of E0. These results demonstrate that the target for chlorination in E0 must be a single tyrosine residue and provide, when taken together with previous findings, the first clear evidence for the identity and location of an active site residue in the polypeptide chain of D-amino oxidase.
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D001665:Binding Sites; D002713:Chlorine / Q000378:metabolism; D002918:Chymotrypsin / Q000378:metabolism; D003605:D-Amino-Acid Oxidase / Q000032:analysis* / Q000378:metabolism; D010455:Peptides / Q000032:analysis*; D014443:Tyrosine / Q000032:analysis*
chemical_list: D000596:Amino Acids; D010455:Peptides; D014443:Tyrosine; D002713:Chlorine; D003605:D-Amino-Acid Oxidase; D002918:Chymotrypsin