Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
16
pubmed:dateCreated
2002-4-18
pubmed:abstractText
Tyrosine hydroxylase (TyrH) is a mononuclear, non-heme iron monooxygenase that catalyzes the pterin-dependent hydroxylation of tyrosine to dihydroxyphenylalanine. When 4-methylphenylalanine is used as a substrate for TyrH, 4-hydroxymethylphenylalanine is one of the amino acid products. To examine the mechanism of benzylic hydroxylation, the products and their isotopic compositions were determined with 4-methylphenylalanines containing a mono-, di-, or trideuterated methyl group as substrates. Intrinsic primary and secondary deuterium isotope effects for benzylic hydroxylation of 9.6 +/- 0.9 and 1.21 +/- 0.08, respectively, were derived from the data. The magnitudes of these isotope effects are consistent with quantum mechanical tunneling of the hydrogen. The similarity of the effects to those seen for benzylic hydroxylation by other enzymes supports a mechanism where a high valence iron-oxo species, Fe(IV)=O, is the hydroxylating intermediate.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0002-7863
pubmed:author
pubmed:issnType
Print
pubmed:day
24
pubmed:volume
124
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
4202-3
pubmed:dateRevised
2008-1-17
pubmed:meshHeading
pubmed:year
2002
pubmed:articleTitle
Intrinsic deuterium isotope effects on benzylic hydroxylation by tyrosine hydroxylase.
pubmed:affiliation
Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't