rdf-syntax-grammar
mods:
  schema location: http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
  title info:
    title: Studies of the chemical mechanism of tyrosine hydroxylase
  name:
    name part: Hillas, Patrick John.
    role:
      role term: creator
  type of resource: text
  genre: bibliography
  origin info:
    place:
      place term: xx
    date issued: 1997
    issuance: monographic
  language:
    language term: eng
  physical description:
    form: print
    extent: xii, 122 leaves : illustrations ; 28 cm.
  abstract: The iron-containing enzyme tyrosine hydroxylase (TYH)
  abstract: catalyzes the hydroxylation of tyrosine to
  abstract: dihydroxyphenylalanine, the initial step in the biosynthesis
  abstract: of the catecholamine neurotransmitters dopamine,
  abstract: norepinephrine, and epinephrine. A series of 4-X-substituted
  abstract: (X=H, F, Br, Cl, CH3, CH30) phenylalanines has been
  abstract: characterized as substrates to gain insight into the
  abstract: mechanism of hydroxylation. Multiple hydroxylated products
  abstract: were formed in most cases. As the size of the substituent at
  abstract: the 4-position increased, the site of hydroxylation switched
  abstract: from the 4- to the 3-position of the aromatic ring. The
  abstract: total amount of product formed with each amino acid showed a
  abstract: good correlation with the [] parameter of the substituent,
  abstract: with [] values of -4.30︢.7 or -5.60︢.8 when
  abstract: tetrahydrobiopterin or 6-methyltetrahydropterin,
  abstract: respectively, was used as cosubstrate. These values are
  abstract: consistent with a highly electron deficient transition state
  abstract: for hydroxylation. Oxygen addition at the 4-position
  abstract: resulted in either elimination of the substituent to form
  abstract: tyrosine or an NIH shift to form the respective 3-X-tyrosine.
  abstract: The relative amount of the product due to an NIH shift
  abstract: decreased in the order Br>CH3>Cl>>F-CH30-0. A labile 4a
  abstract: hydroxytetrahydropterin product was formed with all amino
  abstract: acid substrates tested. For poorly coupled substrates the
  abstract: amount of pterin product formed was greater than the amount
  abstract: of amino acid product formed. A chemical mechanism for
  abstract: hydroxylation by tyrosine hydroxylase is presented to account
  abstract: for amino acid and tetrahydropterin product formation.
  abstract: Formation of the NIH shift product with 4-methylphenylalanine
  abstract: and 4-chlorophenylalanine showed isotope effects of 0.820︢.03
  abstract: and 0.79+ 0.32, respectively. This is consistent with a
  abstract: sequential mechanism where hydroxylation of the aromatic ring
  abstract: occurs before the NIH shift. Studies using 3,4
  abstract: cylohexenylalanie with tyrosine, phenylalanine, and
  abstract: tryptophan hydroxylase showed formation of two products,
  abstract: consistent with discrete attack at either the 3- or 4-carbon
  abstract: and not formation of an epoxide intermediate. Removal of the
  abstract: N-terminal domain of recombinant human phenylalanine
  abstract: hydroxylase relieved allosteric control by phenylalanine.
  abstract: The enzyme's metal content was 0.27 mole Fe per mole enzyme
  abstract: subunit, and it was activated by added iron.
  note: by Patrick John Hillas.
  note: Vita.
  note: "Major Subject: Biochemistry".
  note: Issued also on microfiche from University Microfilms Inc.
  note: Includes bibliographical references: pages 115-119.
  note: Ph. D. Texas A&M University 1997.
  subject:
    topic: Major biochemistry
  identifier: 98-15753 UMI
  identifier: http://proxy.library.tamu.edu/login
  related item:
    location:
      url: http://proxy.library.tamu.edu/login
  record info:
    record content source: TXA
    record creation date: 980701
    record change date: 20190325093514.0
    record identifier: in00001430172