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INHIBITION OF GUINEA‐PIG BRAIN TYROSINE HYDROXYLASE BY CATECHOLS AND BIOPTERIN
Author(s) -
Mann S. P.,
Gordon J. I.
Publication year - 1979
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1979.tb11715.x
Subject(s) - tyrosine hydroxylase , homovanillic acid , biopterin , tyrosine 3 monooxygenase , dopamine , chemistry , catechol , tyrosine , caudate nucleus , guinea pig , enzyme , 3,4 dihydroxyphenylacetic acid , biochemistry , endocrinology , serotonin , biology , tetrahydrobiopterin , cofactor , receptor
—The inhibition by catechols and biopterin of tyrosine hydroxylase from guineapig caudate nuclei has been examined. Inhibitory constants of 10–20 μ m were obtained for dopamine and noradrena‐line and 150–250 μ m for l ‐DOPA and dihydroxyphenylacetic acid. When examined under similar conditions homovanillic acid was found not to be inhibitory. Using an acetone dried powder as the source of tyrosine hydroxylase no change in K m or V max was observed when cyclic AMP or Ca 2+ were added to the medium. Enzyme mechanisms and a possible explanation of the mechanisms controlling catechol synthesis are discussed.