Studies on phenylalanine and tyrosine hydroxylation by rat brain tyrosine hydroxylase

Ira Katz, Thomas Lloyd, Seymour Kaufman

Research output: Contribution to journalArticle

49 Citations (Scopus)

Abstract

Tyrosine hydroxylase (EC 1.14.16.2), presumably the rate-limiting enzyme in the biosynthesis of catecholamines, is known to catalyze the hydroxylation of both phenylalanine and tyrosine. Using both an isolated enzyme preparation and a synaptosomal preparation, where some architectural integrity of the tissue has been preserved, we have attempted to evaluate the manner in which these two substrates are hydroxylated by rat brain tyrosine hydroxylase. In the presence of tetrahydrobiopterin the isolated enzyme catalyzes the hydroxylation of phenylalanine to 3,4-dihydroxyphenylalanine with the release of free tyrosine as an obligatory intermediate. In contrast, the rat brain striatal synaptosomal preparation in the presence of endogenous cofactor converts phenylalanine to 3,4-dihydroxyphenylalanine without the release of free tyrosine.

Original languageEnglish (US)
Pages (from-to)567-578
Number of pages12
JournalBBA - Enzymology
Volume445
Issue number3
DOIs
StatePublished - Oct 11 1976

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Tyrosine 3-Monooxygenase
Hydroxylation
Phenylalanine
Tyrosine
Dihydroxyphenylalanine
Brain
Enzymes
Corpus Striatum
Catecholamines

All Science Journal Classification (ASJC) codes

  • Medicine(all)

Cite this

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Studies on phenylalanine and tyrosine hydroxylation by rat brain tyrosine hydroxylase. / Katz, Ira; Lloyd, Thomas; Kaufman, Seymour.

In: BBA - Enzymology, Vol. 445, No. 3, 11.10.1976, p. 567-578.

Research output: Contribution to journalArticle

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